Closed Comedones vs Milia vs Sebaceous Filaments: Which Bumps Are These?

You looked in the mirror and noticed small bumps on your cheeks, nose, or under your eyes. You tried to squeeze them. Nothing came out. They have been there for weeks, maybe months, and they are not going anywhere.

There are three conditions that match that description: milia, closed comedones, and sebaceous filaments. They look similar from a distance. They are caused by completely different things, and what you do about each one is completely different. Getting the identification right first is the step that makes everything else work, because the right tool for one is the wrong tool for another.

Here is the part most bump guides skip: only one of the three is something a plasma pen should ever touch. We make an at-home pen for milia, and this guide will tell you plainly when you do not need it. For closed comedones and sebaceous filaments, you never do.

What are closed comedones, milia, and sebaceous filaments?

All three share a similar surface appearance: small, pale, and stubbornly resistant to squeezing. That is where the similarity ends. Each one is a different structure inside the skin, which is why the same action, squeezing, produces nothing for all three but for completely different reasons.

What are closed comedones?

Closed comedones are small, skin-colored or faintly white bumps caused by a hair follicle clogged with dead skin cells and sebum (oil) under a thin layer of skin that seals the opening. One bump is a closed comedo; several together read as uneven, bumpy texture, most often on the forehead, chin, cheeks, and jawline.

Unlike milia, a closed comedo does have a follicle underneath, but it is covered. Left alone, it can resolve or it can become inflamed and turn into a whitehead pimple. Unlike a blackhead (open comedo), air never reaches the clog, so there is no oxidation and no dark color. The NIH MedlinePlus skin conditions library classifies comedonal lesions as a subset of acne, specifically the non-inflammatory type.

What are milia?

Milia are tiny keratin cysts that form just below the skin surface. Keratin is the protein that makes up skin, hair, and nails. When a small amount of keratin gets trapped in a sealed pocket beneath the outer skin layer, it forms a hard, white dome. According to the American Academy of Dermatology, milia are extremely common and entirely benign.

A typical milium (singular) is 1 to 2 millimeters across, firm to the touch, bright white or very light yellow, and has no opening. That is why squeezing produces nothing: there is no pore channel for the contents to exit. Milia appear most often under the eyes, on the eyelids, on the cheeks, and on the nose. They are more common after 30, more common in people who use heavy or occlusive skincare products, and more common following skin trauma or sun damage. They do not hurt. They do not itch. They just sit there.

What are sebaceous filaments?

Sebaceous filaments are not a skin problem. They are a normal anatomical feature of the pore. Every active sebaceous (oil) gland has one: a thin, cylindrical sleeve of sebum and dead skin cells that lines the pore channel. This sleeve is what carries oil from the gland to the skin surface. Without it, oil could not get out.

They appear as tiny gray, tan, or skin-colored dots, most visibly on the nose, chin, and central forehead. In good light or with a magnifying mirror, they look like a field of tiny pores filled with something pale. If pressed hard enough, a thin waxy strand can be expressed. The pore refills within 30 days because the gland is still active. Sebaceous filaments are not blackheads. They are not caused by dirt. They are not a sign of poor hygiene. They are a structural feature of healthy skin.

On skin with naturally larger pores or higher oil production the filament is wider and more visible, which is why filaments stand out most on the nose and central face, where oil glands are most active. So when someone tells you "those are sebaceous filaments, not blackheads," the practical meaning is this: there is nothing to extract, only visibility to manage.

Closed comedones vs milia vs sebaceous filaments: how to tell them apart

Look closely at the bump in question. Three features tell you which one it is: texture, whether it has a visible pore, and what happens when you try to compress it gently.

↔ Swipe the table sideways to see the full comparison.

Which one responds to a plasma pen?

Only milia. The plasma pen delivers focused energy precisely to the sealed keratin cyst, disrupting the plug without needing an opening. This is exactly the structure the device is designed for.

Closed comedones and sebaceous filaments need a different approach, and the treatment section below covers exactly what works for each.

Are any of these dangerous?

No. Milia, closed comedones, and sebaceous filaments are all benign. They are not cancerous, not pre-cancerous, not contagious, and not a sign of any underlying medical problem. For the very large majority of people, these are cosmetic concerns, nothing more.

The Mayo Clinic documents milia as a benign skin condition that requires no medical treatment and poses no health risk. The same is true of closed comedones and sebaceous filaments.

When to see a dermatologist instead

The conditions described above do not bleed, grow, or change. If a bump does any of those things, it is not milia, a closed comedo, or a sebaceous filament. See a dermatologist before treating anything yourself if any of the following is true.

Where these three fit in the broader skin-bump family

Understanding the category each condition belongs to makes the treatment logic clearer. Milia are keratin cysts: the smallest and most surface-level members of the cyst family. The same family includes larger epidermoid cysts and steatocystoma, which are oily cysts that also form below the skin but are larger and deeper than milia. All keratin-type cysts respond to energy-based disruption or physical extraction when the structure is accessible.

Closed comedones belong to the comedonal acne family. They are the non-inflamed precursor to whitehead pimples. The whole family responds to keratolytic (skin cell-loosening) agents: salicylic acid, retinoids, and alpha hydroxy acids. These work by thinning the surface skin layer and accelerating cell turnover, which allows plugged follicles to clear. Conditions in this family do not respond well to energy-based devices.

Sebaceous filaments sit in neither family. They are part of the oil gland system itself, which is why no treatment family is designed to remove them.

How to treat closed comedones, milia, and sebaceous filaments

The right treatment depends entirely on correct identification. Each condition has a clear, honest answer.

How to treat closed comedones: topicals, not a pen

Salicylic acid is the front-line treatment for closed comedones. It is oil-soluble, which means it can penetrate the follicle lining where the clog lives. A 2% salicylic acid cleanser or leave-on toner used consistently, once or twice daily, dissolves the plug and prevents new ones from forming. Results take 4 to 6 weeks of consistent use. Adapalene (Differin, available over the counter) is a retinoid that accelerates skin cell turnover, helping clogged follicles clear and preventing future blockages. It can be added after 4 weeks of BHA use or used on its own.

The plasma pen is not appropriate for closed comedones. The clog is inside the follicle channel, not in a sealed surface structure. A pen applied to the surface of a closed comedo treats the skin above the follicle rather than the plug inside, and can cause unnecessary surface irritation.

For milia: plasma pen at home

Milia respond well to plasma pen treatment. The pen delivers focused plasma energy directly to the sealed keratin cyst, disrupting the plug at the source. Because milia have no opening, a pen that reaches the cyst through the skin surface is the correct mechanism. A small scab forms over the treated spot. Over the next 3 to 7 days the scab lifts off on its own. By Week 2 to Week 3 the skin in that area has typically cleared and renewed. One treatment per milium, about 5 minutes for a small cluster.

The OcuraLife Plasma Pen is built for this. It runs at 9 power settings so you can dial the intensity to match the location: milia under the eye need a lower setting than milia on the cheek. Use the lowest setting that produces a visible effect on the spot. Start there and adjust. For a broader look at at-home plasma pen options, see our roundup at best at-home plasma pen 2026. For safety guidance on the device, see is the plasma pen safe.

For sebaceous filaments: manage expectations

There is no treatment that eliminates sebaceous filaments permanently because they are a normal feature of the skin, not a lesion to remove. The realistic goal is to minimize their visibility. Niacinamide at 5 to 10 percent reduces sebum production over 4 to 8 weeks of consistent use, which narrows the filament and makes it less visible. Clay masks provide temporary pore compression for a few hours. BHA toners keep the pore channel clear of excess congestion. These are reasonable tools for a cosmetic concern. Any product or method that claims to permanently eliminate sebaceous filaments is overpromising.

Tiny white bumps appearing after changing your skincare routine

Milia frequently appear, or worsen, after introducing an occlusive product: a heavy eye cream, a thick overnight balm, a rich barrier repair moisturizer. Occlusive products sit on top of the skin and seal moisture in. In areas prone to milia, this occlusion can trap keratin near the surface, providing conditions for a new cyst to form.

If you started noticing small white bumps after adding a new product, particularly under the eyes or on the cheeks, reviewing your product choices is a reasonable first step. Switching to a lighter formulation may slow new milia from forming. It will not resolve existing ones: the keratin cysts that have already formed need direct treatment. This is the most common scenario where at-home plasma pen treatment for milia is clearly appropriate: you know what caused them, you know what they are, and you want them gone without a clinic visit.

For more about skin bump conditions that can appear with skin changes, see our guide to molluscum contagiosum in adults, a different kind of bump that can be confused with milia in some skin textures. For context on dark marks that sometimes follow any skin disruption, see post-inflammatory hyperpigmentation.

"Milia will not respond to squeezing because they have no opening. They respond to precise energy that reaches the keratin plug directly, which is exactly what the plasma pen delivers."

FAQ

Frequently asked questions

Common questions from people trying to identify small facial bumps and understand what to do about them.

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The bottom line

Milia, closed comedones, and sebaceous filaments look alike in the mirror but need three different responses: a plasma pen for milia, salicylic acid and a retinoid for closed comedones, and realistic expectations for sebaceous filaments.

Getting the identification right first is the only step that matters. If your bumps are hard, white, and have no opening, those are milia, and the OcuraLife Plasma Pen is built for exactly that. If your bumps are skin-colored and sit over a follicle, use a BHA. If you see gray dots on your nose that refill after squeezing, those are filaments and no device or product will eliminate them. For other look-alike bumps, browse the full skin conditions library.

The OcuraLife Plasma Pen is a cosmetic device for benign, surface-level spots and is not a substitute for medical advice or diagnosis. If a spot is changing or you are unsure, check with a qualified professional.