Acne Scars: Complete Guide to Types, Causes, and Treatment

Acne scars are one of the most searched skin concerns in dermatology, and one of the most misunderstood. The term covers at least three structurally different types of skin change, each caused by a different healing response and each requiring a different approach. This guide walks through what acne scars actually are, how to tell them apart, what causes them, and what your options are, at the clinic and at home.

What Are Acne Scars?

Acne scars form when an inflamed acne lesion, typically a cyst or deep pustule, damages the dermis: the layer of skin below the surface. When that damage heals, the body either produces too little collagen, leaving a depression in the skin, or too much collagen, leaving a raised area. The medical term is cutaneous scarring secondary to acne vulgaris. In plain English: damaged skin that healed in a way that left a visible texture or color change.

Not every mark left by acne is a scar. Many people confuse post-inflammatory hyperpigmentation, the flat red or brown discoloration that follows a breakout, with an actual acne scar. The distinction matters because the two respond to completely different treatments. That separation is covered in its own section below.

According to the American Academy of Dermatology, acne scarring affects an estimated 95% of people who experience moderate to severe acne at some point. It is one of the most common long-term skin concerns dermatologists see, and it is not a sign of poor hygiene or poor skincare. It is a consequence of deep tissue inflammation. Additional clinical context is available via NIH MedlinePlus.

Types of Acne Scars

Atrophic scars, the most common type, are depressions in the skin where tissue was lost during healing. There are three main sub-types, and distinguishing them matters for treatment decisions.

Ice Pick Scars

Ice pick scars are narrow, deep, and sharply defined. They look like a small puncture or pinprick hole in the skin, typically less than 2 mm across. They are the most difficult to treat because they extend deep into the dermis and sometimes into the subcutaneous tissue beneath. They occur most often on the cheeks, where sebaceous gland density is high. For a detailed comparison of how ice pick scars differ from the other types, see our type identification guide.

Boxcar Scars

Boxcar scars are wider than ice pick scars, with sharply defined vertical edges and a flat or slightly rounded floor. They look like small rectangular or oval craters on the skin surface, typically 1.5 to 4 mm across. They form when inflammation destroys collagen in a localized area without the sharp-edged depth of an ice pick. Boxcar scars respond well to treatments that stimulate new collagen formation because there is tissue to rebuild.

Rolling Scars

Rolling scars give the skin a wave-like or undulating texture. They are caused by fibrous bands of tissue that form between the dermis and the subcutaneous tissue underneath, tethering the skin surface from below. The result is a scar that looks soft at its edges but creates a broader depression. Rolling scars are often more visible in side-lit or raking light. They tend to respond to treatments that break those fibrous attachments.

Hypertrophic and Keloid Scars

A smaller group of people develop raised scars instead of depressed ones. Hypertrophic scars stay within the original wound boundary and may flatten over time. Keloid scars overgrow the original wound boundary and continue to grow. Both are more common in people with darker skin tones and in areas where the skin is under repeated tension, such as the jaw, shoulders, and chest. Raised scars have a different treatment path than atrophic scars and generally require a dermatologist to manage.

Are Acne Scars Permanent?

The honest answer: it depends on the type and depth. Ice pick scars, being the deepest, are the most persistent without intervention. Superficial boxcar and rolling scars improve significantly with the right treatment because the dermis can regenerate collagen when stimulated. Hypertrophic scars often soften on their own over 12 to 18 months. Keloid scars do not resolve without treatment.

Post-inflammatory hyperpigmentation, the flat red or brown marks that look like scars, is not a true scar. PIH is melanin overproduction in response to inflammation and fades on its own in 3 to 12 months for most people, faster with consistent SPF use and certain topical ingredients. Time is its treatment. True atrophic scarring does not fade on its own because the collagen architecture underneath the surface has changed structurally, not just in color.

For a focused answer to this question, see Do Acne Scars Fade on Their Own?

Acne Scars vs Post-Inflammatory Hyperpigmentation: What Is the Difference?

This is the most useful clinical distinction to understand before pursuing any treatment. Getting it wrong means spending time and money on a product that treats the wrong thing.

The quick test: run your finger across the mark in low light. If it is flat and only a color difference, you are looking at PIH. If there is a depression or elevation, you have a scar. Most people in their 30s and 40s dealing with "acne scars" have a mix of both, and understanding which is which tells you where to focus. This distinction also separates acne scarring from other face-texture conditions like sebaceous hyperplasia, where the lesion is a raised oil gland rather than a depressed scar.

What Causes Acne Scars?

The underlying cause is always inflammation. But not all acne causes scarring. The factors that increase scarring risk are:

Lesion Depth and Severity

Superficial whiteheads and blackheads almost never scar because they sit at the surface. Cystic acne, nodular acne, and deep pustules reach into the dermis and damage the collagen framework. The deeper the inflammation, the higher the scar risk. This is why hormonal cystic acne, which tends to be nodular and concentrated on the chin, jaw, and cheeks, leaves more scarring than teen whiteheads.

Delayed or Disrupted Healing

Picking, squeezing, or manipulating a lesion extends the inflammatory window, introduces bacteria into a deeper plane of the skin, and almost always worsens the scar outcome. The fingernail introduces contamination and pushes infected content deeper into the dermis. If you have a habit of picking, the scar outcome will be worse than if you leave lesions alone.

Acne Scars on Darker Skin Tones

People with medium to deeper skin tones are more susceptible to post-inflammatory hyperpigmentation AND to hypertrophic or keloid scarring. The melanocyte response to inflammation is more robust. This means PIH marks are darker, last longer, and can be triggered by less severe acne. It also means treatment choices matter more: certain laser settings and chemical peel concentrations that are safe for lighter skin tones carry a higher risk of hyperpigmentation or hypopigmentation in darker tones. Any at-home treatment in this group should start at the lowest intensity settings.

Genetic Predisposition

Some people consistently scar more from comparable acne severity than others. The tendency to produce excess or insufficient collagen in response to tissue damage is partly genetic. If a parent or sibling has significant acne scarring, your own risk is elevated.

How Do Dermatologists Treat Acne Scars?

Clinical treatment options depend entirely on scar type. No single modality treats all types equally. A dermatologist will typically assess the mix of scar types present before recommending a treatment plan.

For Ice Pick Scars

TCA cross (trichloroacetic acid applied at very high concentration directly into the ice pick channel) is the most effective in-office approach. It stimulates collagen growth inside the channel. Punch excision, where the scar is surgically removed and the edges sutured, is used for very deep or wide ice pick scars. Multiple sessions are standard.

For Boxcar and Rolling Scars

Microneedling (radiofrequency or standard) and resurfacing lasers (ablative CO2, erbium) are the primary approaches. Both trigger a collagen-production response by controlled wounding of the dermis. Subcision, where a needle is inserted under the skin to break fibrous tethering bands, is particularly effective for rolling scars. Dermal fillers can temporarily lift boxcar and rolling scars, though this does not change the underlying structure.

For Raised Scars

Intralesional corticosteroid injections flatten hypertrophic scars over time. Silicone sheeting is recommended for maintenance. Keloid management requires specialist care and often a combination of corticosteroids, silicone, and laser. Clinical treatments for acne scarring typically start at $200 to $400 per session for microneedling and reach $800 to $2,000+ per session for ablative laser resurfacing. Multiple sessions are almost always required.

Can You Remove Acne Scars at Home?

Yes, for certain scar types and depths, with realistic expectations. Superficial boxcar and rolling scars respond to treatments that stimulate collagen production in the dermal layer, and plasma energy works by the same mechanism as electrocautery-based clinical treatments. At-home plasma pen use targets the surface of the scar bed and triggers a localized healing response, which stimulates new collagen formation as the treated skin renews.

The OcuraLife 6-in-1 Skin Imperfection Removal Pen uses plasma energy delivered at 9 power settings, allowing you to calibrate the intensity to the depth and sensitivity of the scar location. The device is designed for at-home use on benign skin changes including acne scars, within the bounds of reasonable scar depth and accessibility. The same collagen-renewal mechanism applies to related texture conditions like stretch marks.

For a step-by-step at-home treatment protocol, see How to Fade Acne Scars at Home. For a head-to-head comparison of plasma pen, microneedling, and TCA for acne scars, see Plasma Pen vs Microneedling vs TCA for Acne Scars.

Important scope: very deep ice pick scars, raised hypertrophic or keloid scars, and scars in locations near the eyes are not appropriate for at-home plasma treatment. When in doubt about scar type or depth, a dermatologist assessment is the right first step.

What to Expect: The Treatment Timeline

At-home plasma pen treatment follows a predictable healing sequence for each treated spot.

Day 0: Treatment (Approximately 5 Minutes Per Spot)

The plasma tip is held close to the scar surface without contact. A small arc delivers plasma energy directly to the spot. A tiny protective scab begins to form immediately. Keep the area clean and dry after treatment.

Day 3 to Day 7: Natural Healing

The protective scab remains in place. Do not pick or scrub it. The skin is rebuilding underneath. Healing Patches can shield the spot from friction and accidental picking during this window. Sun protection is important even during the healing phase.

Week 2 to Week 3: Clear Skin Visible

The scab has fallen off on its own. The skin in that area has renewed. The collagen stimulation continues beneath the surface for weeks after the visible scab is gone. SPF 50 is essential during this period, as newly treated skin burns more easily and unprotected sun exposure can trigger PIH in the healing zone. Deeper or older scars may benefit from a second session once the first healing cycle is complete, typically 4 to 6 weeks later.

When Should You See a Doctor Instead?

Bypass at-home treatment and see a dermatologist if any of the following applies.

See Mayo Clinic's acne overview and the American Academy of Dermatology for clinical guidance on when inflammatory acne itself requires a dermatologist visit. Uncontrolled active acne should be addressed before scar treatment begins.

"The most important first step is identifying which type of acne scar you have, because the identification tells you which treatments are appropriate and which to skip entirely."

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The Bottom Line

Acne scars are common, manageable, and not a life sentence. The most important first step is identifying which type you have, because the identification tells you which treatments are appropriate. PIH is not a scar and will fade with time and SPF. Ice pick scars are best addressed clinically. Superficial boxcar and rolling scars respond well to collagen-stimulating treatments, including at-home plasma energy.

If you are confident you have superficial atrophic scarring and want to treat it at home, the OcuraLife 6-in-1 Skin Imperfection Removal Pen uses plasma energy to stimulate the collagen-renewal response that gradually improves the texture of treated scars. The step-by-step guide below walks through doing it correctly.

Related guides in this cluster

• How to Fade Acne Scars at Home (the treatment protocol)
• Boxcar vs Ice Pick vs Rolling Acne Scars: How to Identify Yours (type identification)
• Plasma Pen vs Microneedling vs TCA for Acne Scars: The Comparison (method comparison)
• Do Acne Scars Fade on Their Own? The Honest Answer (resolution Q&A)