Acne scarring is permanent texture change in the skin caused by the body’s wound healing response to inflamed breakouts. It affects a striking number of people: roughly 95% of those with acne develop some degree of scarring, and in clinical studies, visible scarring shows up in about 71% of acne patients. The scars form when deep inflammation from acne disrupts the normal production and breakdown of collagen in the skin, leaving behind depressions, raised tissue, or both.
How Acne Scars Form
Every acne lesion triggers inflammation, and that inflammation begins earlier than most people realize. It starts at the microscopic stage, before a pimple is even visible, and persists through every phase of a breakout’s life cycle. When the lesion finally resolves, the skin attempts to repair itself. In most cases, the repair process goes wrong in a specific way: the body either destroys too much collagen or produces too much of it.
In 80 to 90% of acne scars, the problem is a net loss of collagen in the deeper layers of skin. This creates indented, sunken scars. In the remaining cases, the body overproduces collagen, resulting in raised scars that sit above the skin’s surface. Inflammatory cells are found in 77% of indented scars, confirming that ongoing inflammation is the central driver.
Interestingly, people who are prone to scarring have a different immune response than those who aren’t. In scar-prone individuals, the initial immune reaction to a breakout is smaller and slower, with fewer immune cells arriving early. But as the lesion heals, the immune response ramps up and becomes more active, essentially arriving late and overcompensating. This delayed, disorganized healing is what tips the collagen balance in the wrong direction.
Types of Indented (Atrophic) Scars
Since collagen loss accounts for the vast majority of acne scars, most people dealing with scarring have one or more of three distinct indented scar types. They often appear together on the same face.
- Ice pick scars are small, narrow indentations that taper downward into the skin like a puncture. They’re typically the deepest type relative to their size, which makes them among the most stubborn to treat.
- Boxcar scars are broader depressions with sharp, well-defined edges, giving them a box-like appearance. They can be shallow or deep, and their flat base distinguishes them from ice pick scars.
- Rolling scars have sloping, irregular edges and varying depth, which creates a wavy, uneven texture across the skin. Fibrous bands beneath the surface tether the skin downward, pulling it into these soft undulations.
Raised Scars: Hypertrophic and Keloid
When the body produces excess collagen during healing, the result is a raised scar. These fall into two categories that look similar but behave differently.
Hypertrophic scars stay within the boundaries of the original breakout. They contain whorled bundles of collagen and may flatten somewhat over time. They’re most common in areas where the skin crosses joints or creases, where repeated movement creates tension during healing.
Keloid scars grow beyond the edges of the original wound, sometimes significantly. They contain thicker, abnormally assembled collagen bundles with less cross-linking between fibers. Keloids tend to appear on the chest, shoulders, back, neck, and earlobes, areas associated with higher skin tension and constant stretching during everyday movement. Unlike hypertrophic scars, keloids rarely improve on their own and can continue expanding for months or years.
What Increases Your Risk
The single biggest factor is untreated or undertreated inflammatory acne. The longer and more severely your skin stays inflamed, the more opportunities there are for the healing process to go wrong. Clinical data backs this up in a way that might surprise you: patients treated only with topical products had roughly double the odds of developing scars compared to untreated patients, and those treated with oral antibiotics alone had four times the odds. This doesn’t mean those treatments cause scarring. It reflects the fact that patients with more severe, persistent acne are the ones receiving these treatments, and the treatments alone may not be enough to prevent the underlying collagen damage.
One medication stood out as protective. Isotretinoin (the active ingredient in drugs formerly known by the brand name Accutane) was associated with a 91% reduction in the odds of scarring. This reinforces what dermatologists increasingly emphasize: early, aggressive management of inflammatory acne is the most effective way to prevent scars from forming in the first place.
Preventing Scars Before They Start
The best evidence for scar prevention centers on controlling inflammation quickly and consistently. Current guidelines recommend topical retinoids or combination products for mild to moderate acne, with oral medications or isotretinoin reserved for more severe or nodular cases. The initial treatment goal is typically greater than 50% clearance, followed by ongoing topical maintenance to prevent relapse.
For the first time, there’s also clinical evidence that a specific topical combination (adapalene with benzoyl peroxide) can reduce the number of atrophic scars that form over a six-month period. This is notable because it represents a shift from only treating scars after they’ve formed to actively preventing them during active breakouts.
How Existing Scars Are Treated
No single treatment works for every type of scar, and most people see the best results from combining approaches. The goal is to stimulate new collagen production in areas where it’s been lost, or to remodel excess collagen in raised scars.
Microneedling
Standard microneedling uses tiny sterile needles to create controlled micro-injuries in the skin. These small punctures trigger the body’s natural healing response, prompting new collagen and elastin production. It works best for shallow to moderate scarring and produces gradual improvement over multiple sessions.
Radiofrequency (RF) microneedling adds heat energy delivered through the needles directly into the deeper layers of skin. This combination reaches tissue that standard microneedling can’t, causing existing collagen to contract and stimulating more significant long-term remodeling. The heat also softens the fibrous strands that pull skin downward in rolling scars. Results from RF microneedling continue improving for several months after treatment and tend to last longer than standard microneedling alone.
Fractional Laser Resurfacing
Fractional lasers vaporize microscopic columns of damaged skin, leaving surrounding tissue intact to speed healing. After a series of four to six sessions spaced about 30 to 45 days apart, ablative fractional resurfacing improves the depth and appearance of acne scars by as much as 50%. Some studies have documented scar depth improvements of up to 66% in certain patients. For people with darker skin tones, treatment settings need careful adjustment to minimize the risk of post-treatment discoloration.
Subcision
For scars tethered to deeper tissue, particularly rolling scars, subcision involves inserting a needle beneath the scar to physically release the fibrous bands pulling the skin down. This allows the skin to lift back to a more even surface and triggers new collagen formation in the released space. Subcision is often combined with other treatments like fillers or microneedling for more complete correction.
Redness and Dark Marks vs. True Scars
Not every mark left behind by acne is a permanent scar. Post-inflammatory redness (often called PIE) results from tiny dilated blood vessels near the skin’s surface, made more visible by temporary thinning of the outer skin layer during healing. It appears as flat pink or red patches and fades on its own over weeks to months, though it can persist longer in lighter skin tones.
Post-inflammatory hyperpigmentation (PIH) shows up as flat brown or dark spots, particularly in medium to dark skin tones. These marks are caused by excess melanin deposited during the healing process, not by collagen damage. Neither PIE nor PIH involves a change in skin texture. If the mark is flat and smooth when you run your finger over it, it’s likely discoloration rather than a true scar, and it will generally resolve without procedural treatment.