Scarring is your body’s natural repair process after skin or tissue is damaged. When a wound goes deeper than the surface layer of skin, the body fills the gap with a protein called collagen, creating a patch that’s structurally different from the original tissue. This repaired area is a scar. Every scar tells the same biological story: the body prioritized closing a wound quickly over rebuilding the tissue exactly as it was.
How Scars Form
Scar formation happens in three overlapping phases. The first is inflammation, which starts immediately after an injury. Blood vessels constrict, platelets clump together to stop bleeding, and white blood cells flood the area to clear out bacteria and debris. This phase lasts several days and is why fresh wounds look red and swollen.
Next comes the proliferative phase, which can last several weeks. This is the construction phase. Specialized cells called fibroblasts move into the wound and begin producing collagen, the main structural protein in skin. By days five through seven, these cells are actively laying down new collagen fibers and building a scaffold that stabilizes the wound. New blood vessels grow into the area to supply nutrients, and the surface layer of skin starts creeping across the gap.
The final stage, remodeling, begins around week three and can continue for up to 12 months. During this phase, the body breaks down excess collagen and reorganizes what remains. The scar gradually flattens, softens, and fades. This is why a scar that looks angry and raised at two months can look dramatically better at one year. Peak wound contraction, where the scar physically tightens and shrinks, also happens around week three.
Why Scar Tissue Differs From Normal Skin
Scar tissue is not just “new skin.” It’s a fundamentally different material. In normal skin, collagen fibers are arranged in a loose, somewhat random basket-weave pattern. In scar tissue, those fibers line up in a much more parallel orientation, with tighter, smaller bundles. Research measuring collagen alignment found that scar tissue scored 0.44 on an orientation index compared to 0.26 for normal skin, meaning scar collagen is significantly more organized and directional.
This parallel structure is what makes scars feel stiffer and less flexible than the surrounding skin. Scar tissue also lacks the features that make normal skin functional: hair follicles, sweat glands, and oil glands don’t regenerate within a scar. That’s why scars don’t tan the same way, don’t grow hair, and can feel drier than the skin around them.
Types of Scars
Not all scars behave the same way. The type you end up with depends on how much collagen your body produces during healing and whether it knows when to stop.
Flat (Mature) Scars
Most scars follow the normal trajectory: red and slightly raised at first, then gradually flattening and fading over months. These mature scars are pale, flat, and soft. They’re the most common outcome of cuts, surgical incisions, and minor injuries.
Hypertrophic Scars
When the body overproduces collagen and the inflammation phase drags on, the result is a hypertrophic scar. These are raised, thick, and often red or pink. They can be itchy or even painful during the active phase of collagen buildup, which can last 6 to 12 months. The key feature of a hypertrophic scar is that it stays within the boundaries of the original wound, even if it widens. If a wound takes longer than two weeks to fully close over with new skin, the risk of hypertrophic scarring increases, especially in children and adults under 40.
Keloid Scars
Keloids go a step further. Unlike hypertrophic scars, keloids grow beyond the edges of the original injury and can continue expanding even years later. They often have a mushroom or cauliflower-like appearance and are frequently painful or itchy. The center of a keloid is dense and relatively inactive, while the outer edge is where active growth and inflammation occur. Keloids are notoriously difficult to treat because they tend to recur.
Atrophic Scars
These scars are sunken or depressed rather than raised. They form when the body produces too little collagen during healing. Stretch marks are one common example. Acne scars are another, and they come in three distinct shapes: ice pick scars (narrow, deep, and sharp-walled), rolling scars (broad depressions with a wavy texture caused by fibrous bands pulling the skin down from underneath), and boxcar scars (wider depressions with defined vertical edges, almost like a small crater).
Contracture Scars
Contracture scars form after large areas of skin are lost, typically from burns. As the scar tissue matures and tightens, it pulls the surrounding skin inward. When this happens over a joint, the tightening can seriously limit movement. Over years, a contracture that isn’t treated can shorten the muscles, tendons, and even blood vessels beneath it. In severe cases, joints can become partially dislocated, and the deeper structural changes may be only partially reversible even with surgery. Early, sustained stretching during the healing period can help because newly formed scar collagen is still somewhat flexible before it fully cross-links and hardens.
Scarring Inside the Body
Scarring isn’t limited to the skin. After abdominal or pelvic surgery, internal scar tissue can form bands called adhesions that connect organs to each other or to the abdominal wall. These adhesions are made of the same basic material as external scars: dense collagen, blood vessels, and inflammatory cells.
Many people with adhesions never know they have them. But for others, adhesions cause significant problems, including bowel obstruction, chronic pelvic pain, and female infertility (when scar bands distort the reproductive organs and block the normal movement of an egg). Adhesions are one of the most common complications of abdominal surgery and a frequent reason for repeat operations.
What Affects How You Scar
Several factors influence whether a wound heals with a barely visible line or a prominent scar. Age plays a role: younger skin tends to produce more collagen and has a higher rate of hypertrophic scarring. People over 65 generally scar less aggressively. Wound location matters too, with scars on the chest, shoulders, and upper back more prone to becoming raised, while facial skin tends to heal with less visible scarring.
Genetics are a significant factor. Research on burn patients found that certain racial and ethnic backgrounds carry higher risk for hypertrophic scarring, suggesting undiscovered genetic variants influence the scarring process. Larger and deeper wounds produce more prominent scars, as do wounds that take longer to close. Infection during healing almost always worsens the final scar because it prolongs the inflammatory phase.
Helping Scars Heal Well
The single most important thing you can do for a healing scar is keep it moist. A moisture-rich environment speeds the regrowth of the skin’s surface layer and reduces excess collagen production. Petroleum jelly applied three times daily for one to three weeks after a wound closes is a simple, effective option. Paper tape placed over the wound for at least six weeks also helps by keeping the area moist and preventing scab formation.
Silicone gel sheets are one of the most studied scar treatments. They work primarily through occlusion, essentially acting as an artificial barrier that prevents water loss from immature scar tissue. When a new scar loses too much moisture, the resulting increase in sodium concentration at the skin’s surface triggers inflammatory signaling that promotes excess collagen production. Silicone sheets interrupt that cycle. For best results, they should be worn at least 12 hours a day for three to four months, but no longer than six months total.
Sun protection is critical during the first 18 months. New scar tissue is highly vulnerable to ultraviolet radiation, which can cause permanent darkening (hyperpigmentation) and structural damage to the collagen matrix. Covering the scar with clothing is the most reliable protection. When the scar is exposed, sunscreen with an SPF of at least 30 should be applied consistently for 12 to 18 months after the injury.