Why Acne Scars Form - and What You Can Actually Do About Them

Your breakout finally cleared, but it left something behind - a dark patch, a red mark, or a small dent that won't go away. You assume it's a scar and brace yourself for it being permanent. Often, it isn't.

Acne scars and post-acne marks are not the same thing, and the treatment for one doesn't work for the other. Most people have one or both and don't know which. Here's the difference, why each one forms, and what the evidence actually supports for treating them.

Marks vs. Scars: The Distinction That Matters

Post-inflammatory hyperpigmentation (PIH) is what most people mean when they say acne scars. It's the dark, brown, or red mark left after a spot heals - a flat area of discoloration caused by the melanin overproduction that inflammation triggers. These are not scars. They're pigmentation changes, and they usually fade, often completely, with time and the right care - though in darker skin tones they can take longer and don't always clear entirely.

True acne scars are structural changes to the skin - depressions or raised areas where the dermis has been physically altered by inflammatory damage. They don't fade with skincare the way pigmentation does, and they call for more targeted treatment.

A quick way to tell them apart: if the skin is smooth to the touch but discolored, it's likely a mark. If you can feel a dent, pit, or raised bump, it's likely a scar.

Why True Scars Form

Scarring happens when inflammation is severe and deep enough to damage the collagen in the dermis - the layer beneath the surface that gives skin its structure. When a cystic spot ruptures, the follicle wall breaks and its contents spill into the surrounding tissue, setting off a strong inflammatory response. The skin repairs the damage with new collagen, but that collagen is often different in texture, density, and arrangement from the original.

Most acne scars are atrophic, meaning they form when too little collagen is laid down during healing, leaving a depression. They come in a few recognizable shapes:

Less commonly, acne produces hypertrophic scars, where too much collagen is deposited and a raised area forms.

The single biggest risk factor for scarring is picking and squeezing spots. Every time you manually rupture a follicle, you push inflammation deeper, introduce bacteria from your hands, and sharply raise the odds of permanent structural change.

• Icepick scars: narrow and deep, like a small puncture
• Boxcar scars: wider, round or oval, with defined edges
• Rolling scars: broad with a wavelike, undulating surface from fibrous tissue tethering the skin downward

What Actually Works for Pigmentation

Post-acne marks respond to time, sun protection, and the right active ingredients. UV exposure is the main obstacle - it directly stimulates the melanin production that's already elevated in the affected area, deepening marks and prolonging how long they take to fade. Daily broad-spectrum SPF is the non-negotiable baseline that every other treatment depends on.

Several ingredients have good evidence for PIH, and they work at different points in the pigment pathway:

Used consistently and paired with daily sun protection, these can meaningfully speed up fading. Marks often improve over weeks to months rather than days, so patience matters.

• Tranexamic acid: calms the inflammatory signaling that drives excess melanin production
• Niacinamide: blocks the transfer of pigment from melanocytes to surface skin cells
• Azelaic acid: inhibits tyrosinase, a key enzyme in melanin synthesis
• Retinoids: speed cell turnover, shedding pigmented cells faster, and support collagen

What Actually Works for True Scars

Topical skincare can improve the look of shallow atrophic scars - retinoids stimulate collagen production and can soften scar edges over time - but it can't reverse structural changes to the dermis. For more significant scarring, the evidence points to in-office procedures.

The American Academy of Dermatology notes that treatments like microneedling, laser resurfacing, chemical peels, and subcision (used specifically for rolling and tethered scars) have clinical evidence behind them, and that combining approaches often works better than any single one because most people have more than one scar type. These procedures are outside the scope of what Nolla prescribes. If scarring is a real concern for you, a consultation with a board-certified dermatologist who performs these procedures is worth pursuing.

The Most Effective Thing You Can Do Right Now

Treat your acne effectively and stop picking. The best scar prevention is preventing the inflammatory damage that causes scars in the first place. Every cystic spot you head off with consistent treatment is a scar that never forms, and every spot you leave alone instead of squeezing is a recovery that stays at the surface rather than going deep.

If your acne is painful, cystic, or leaving marks and dents despite over-the-counter products, that's a signal to get a personalized plan from a clinician rather than waiting it out. Earlier, effective control of inflammation is the most reliable way to protect your skin from lasting scars.