Acne scars fall into two broad categories: indented scars that sit below the skin’s surface and raised scars that build up above it. Most acne scars are indented, caused by tissue loss during the healing process, and they come in three distinct shapes. Flat discolored marks that many people call “scars” are often something different entirely.
Indented Scars: The Most Common Type
The vast majority of acne scars are atrophic, meaning the skin dips inward where a breakout once was. This happens when inflammation destroys collagen in the deeper layers of skin and the body can’t fully rebuild it. These scars come in three recognizable shapes, and many people have a mix of all three.
Ice Pick Scars
These are small, deep holes that look like someone poked the skin with a sharp instrument. They’re narrow, less than 2 mm across, with steep walls that extend deep into the skin. Under a microscope, they can reach nearly 4 mm deep, making them the deepest of the three types despite being the smallest on the surface. Ice pick scars are most common on the cheeks and tend to look like enlarged, very deep pores.
Boxcar Scars
Boxcar scars are wider, round or oval depressions with sharp, clearly defined edges. They look similar to chickenpox scars. Most are 1.5 to 4 mm in diameter, and they come in shallow and deep varieties. Shallow ones dip less than half a millimeter below the surrounding skin, while deep ones go further. The key visual feature is their well-defined borders: you can see exactly where normal skin ends and the scar begins, almost like a small crater with vertical walls.
Rolling Scars
Rolling scars are the widest type, typically more than 4 to 5 mm across, but with soft, sloping edges that blend gradually into surrounding skin. They create a wavy, uneven texture that’s most visible in angled lighting. The undulating appearance comes from bands of scar tissue underneath that pull the surface of the skin downward. Rolling scars tend to become more noticeable with age as skin loses firmness and these tethered areas become more pronounced.
Raised Scars: Hypertrophic and Keloid
Some acne scars do the opposite of sinking in. They rise above the skin because the body overproduces collagen during healing. There are two types, and they look quite different from each other.
Hypertrophic scars are slightly raised or flat, pink to red in color, and stay within the boundaries of the original breakout. They’re firm to the touch but don’t spread. Over time, many flatten on their own.
Keloids are more dramatic. They’re firm, smooth, raised bumps with a purplish-red color that grow beyond the edges of the original wound. A keloid from a pimple on your jawline, for example, can eventually extend onto skin that was never affected by acne. They’re more common on the chest, shoulders, and back, where skin is thicker and under more tension. People with darker skin tones are more prone to both hypertrophic and keloid scarring.
Where Different Scars Tend to Appear
Location matters. Facial skin is thinner with a richer blood supply, which generally helps it heal with less raised scarring. Ice pick, boxcar, and rolling scars are overwhelmingly found on the cheeks, temples, and forehead. The chest, shoulders, and upper back tell a different story. Skin in these areas is thicker and under greater mechanical tension from everyday movement, which increases the likelihood of raised or hypertrophic scarring. If you’ve had acne on your back or chest, you’re more likely to see firm, raised scars there than indented ones.
Flat Marks That Aren’t Actually Scars
Many people mistake flat discolored spots for scars, but these are a separate issue. After a pimple heals, it often leaves behind a colored mark on otherwise smooth skin. If the texture is flat, meaning you can’t feel a dip or bump when you run your finger over it, what you’re seeing is post-inflammatory discoloration rather than a true scar.
What color the mark is depends largely on your skin tone. On lighter skin (typically Fitzpatrick types I through III), these marks tend to be pink or red. This is called post-inflammatory erythema, and it’s caused by lingering blood vessel changes in the skin from inflammation. On darker skin tones (Fitzpatrick types III through VI), the marks are more likely to appear brown, dark brown, or even grayish. This is post-inflammatory hyperpigmentation, caused by excess melanin production triggered by the same inflammatory process.
The important distinction: these flat marks fade over time, though hyperpigmentation in darker skin can take months or even years without treatment. True scars involve a change in skin texture, either a depression or a raised area, and don’t resolve on their own.
How to Tell What Type You Have
The simplest way to identify your scars at home is to stretch the skin gently with two fingers. Rolling scars tend to disappear or flatten out when you stretch the skin because the issue is tethering underneath, not missing tissue. Ice pick and boxcar scars remain visible because the tissue loss is structural. Raised scars are easy to identify by touch alone.
Lighting also changes how scars look dramatically. Indented scars are most visible in harsh, angled light (like direct sunlight coming from one side) because the shadows they cast make the depth more obvious. In soft, diffused light, the same scars can be nearly invisible. This is why acne scars often look worse in bathroom mirrors with overhead lighting than they do in natural, even light.
About 20% of people with acne develop a severe form of the condition, and severe acne is the biggest risk factor for permanent scarring. But even moderate acne can leave marks, especially if breakouts are picked at or left untreated for extended periods. Most people with acne scars have a combination of scar types rather than just one, which is why the skin’s texture can look varied across different areas of the face.