An indented scar forms when your skin loses tissue during healing and doesn’t produce enough collagen to fill the gap back in. In 80 to 90 percent of cases where acne causes scarring, the result is a net destruction of collagen in the deeper layers of skin, leaving a visible depression. This same process can happen after chickenpox, surgery, injuries, or any wound that damages tissue beneath the surface.
How Collagen Loss Creates the Indentation
When your skin is injured, it kicks off a healing process that involves building new collagen, the structural protein that gives skin its firmness and volume. In a normal wound, your body produces roughly the right amount of collagen to fill the damaged area and restore a relatively smooth surface. But when too much collagen gets broken down during healing, or too little gets produced, the repaired skin sits lower than the surrounding tissue. That sunken area is what you see as an indentation.
The key player here is a balance between collagen production and collagen degradation. If the balance tips toward excess degradation, you end up with an atrophic (indented) scar. If it tips the other way, toward overproduction, you get a raised scar like a keloid. Most scars from acne, chickenpox, and minor injuries fall into the indented category because the inflammation that caused them also destroyed the underlying support structure of the skin.
Why Inflammation Makes It Worse
There’s a direct link between how inflamed a wound gets and how severe the resulting scar turns out. More inflammation means more tissue destruction, which means a deeper indentation. This is why deep, painful acne cysts tend to leave worse scars than mild breakouts. The longer and more intensely the skin stays inflamed, the more collagen and fat tissue get broken down beneath the surface.
Picking at acne, scratching chickenpox blisters, or repeatedly irritating a healing wound all extend the inflammatory phase. That prolonged inflammation overlaps with later stages of healing and disrupts the rebuilding process. Wounds that heal with minimal inflammation, by contrast, tend to produce significantly less scarring.
Common Causes of Indented Scars
Acne is the most common culprit. Inflammatory acne lesions, particularly cysts and nodules, can permanently damage the skin’s deeper layers. Atrophic scars are the most common type of acne scar by a wide margin.
Other frequent causes include chickenpox (the blisters destroy small pockets of tissue), surgical incisions that heal under tension or with excessive tissue loss, and traumatic injuries where skin tissue is physically removed. Even minor wounds can leave indentations if the healing process is disrupted by infection, repeated trauma, or poor blood supply to the area.
Types of Indented Scars
Not all indented scars look the same. Dermatologists generally classify them into three shapes, each reflecting a different pattern of tissue loss:
- Ice pick scars are narrow, deep, and V-shaped, like a tiny puncture in the skin. They’re usually the hardest to treat because the damage extends deep into the dermis.
- Boxcar scars are round or oval depressions with sharply defined edges, almost like a small crater. They can appear skin-colored, reddish, or dark brown depending on your skin tone.
- Rolling scars are wider and shallower with sloped edges, creating a wave-like unevenness across the skin. These form when fibrous bands of scar tissue pull the surface of the skin downward from underneath.
Many people have a mix of all three types, especially after years of acne.
When an Indentation Becomes Permanent
After a wound closes, the scar enters a maturation phase that lasts several months. During this time, the body continues remodeling the tissue: inflammation gradually decreases, blood vessels recede, and collagen fibers reorganize. An immature scar may still improve somewhat during this window. Once the remodeling process is complete, the scar’s depth and texture are largely set. If an indentation is still visible after about a year, it’s unlikely to fill in on its own.
Treatments That Reduce Scar Depth
Subcision
Subcision works by physically breaking the fibrous bands that tether an indented scar to deeper tissue. A small instrument is inserted beneath the scar to detach it from the underlying layer, allowing the skin to lift. The controlled injury also triggers new connective tissue growth that fills in the space underneath. Subcision alone shows clinical improvement in about 67% of patients, but when combined with suctioning afterward, improvement jumps to roughly 72%. Pairing subcision with injectable fillers pushes that number even higher, with one study showing significant improvement in over 94% of patients.
Laser Resurfacing
Fractional CO2 lasers create tiny columns of controlled damage in the skin, leaving untouched skin between each column. This triggers the body to produce fresh collagen as it heals those microscopic channels, gradually raising the scar’s surface. A series of four to five monthly treatments can improve scar depth and appearance by as much as 50%. Some studies report scar depth improvements of up to 67% in patients with moderate to severe scarring. Sessions typically cost $800 to $1,500 each.
Microneedling
Microneedling uses fine needles to create tiny punctures in the scar tissue, stimulating collagen production through a similar wound-healing response. It’s generally less expensive than laser treatment (around $500 per session) and tends to cause less discomfort and downtime. Head-to-head comparisons are mixed: some studies find fractional CO2 lasers produce better results in texture and contour, while others show both methods are equally effective. Microneedling with radiofrequency may be the better option for darker skin tones, where laser treatments carry a higher risk of pigmentation changes.
Dermal Fillers
Fillers work by physically adding volume beneath the indentation to raise it to the level of surrounding skin. How long the results last depends on the type. Hyaluronic acid fillers are temporary, lasting up to 18 months. Semi-permanent options that stimulate your body’s own collagen production can last two to three years. One permanent filler received FDA approval specifically for moderate to severe atrophic acne scars in 2014, with patients in one study followed for up to nine years. Fillers are often most effective when combined with subcision or laser treatments rather than used alone.
Reducing Indentation Risk During Healing
The single most important factor in preventing an indented scar is controlling inflammation while the wound heals. For acne, that means treating active breakouts early and avoiding picking or squeezing, which drives inflammation deeper into the skin. For surgical wounds, keeping the wound edges together without tension allows the new tissue to develop smoothly into skin-like tissue rather than collapsing into a depression. Keeping any healing wound clean, moist, and protected from repeated trauma gives your body the best chance of maintaining that collagen balance on the production side rather than the destruction side.