Scarring begins during the final phase of wound healing, known as remodeling, which starts around week three after injury and can continue for 12 months or longer. In a deep wound, the body cannot perfectly reconstruct the original tissue. Instead, it fills the gap with a denser, less flexible material that restores function quickly but never fully matches the skin it replaced. A mature scar reaches only about 80% of the tensile strength of normal, undisrupted skin.
Why Deep Wounds Scar Instead of Regenerating
Your skin heals in overlapping stages. First, bleeding stops and inflammation clears debris over several days. Then, over the following weeks, new blood vessels and temporary tissue fill the wound. This early repair tissue is built largely from thin, fast-turnover fibers (a juvenile form of the protein collagen) that act as a rough scaffold.
The shift toward permanent scarring happens in the remodeling phase. The body gradually replaces those thin, temporary fibers with thicker, more mechanically stable ones. This swap is what transforms a healing wound into a scar. The new fibers are laid down in a parallel, organized pattern rather than the basket-weave arrangement found in uninjured skin. That structural difference is why scars look and feel different from the surrounding tissue, even years later.
How Specialized Cells Shape the Scar
A key driver of scarring is a specialized cell that acts like a tiny muscle within the wound. These cells grip the surrounding collagen mesh and pull it inward, physically shrinking the wound. Each individual cell contracts only a tiny distance, but because they work through an interconnected network, the collective effect is significant. This contraction is what closes a deep wound from the inside.
The trade-off is imperfect healing. The body prioritizes rapid closure over restoring the tissue to its original state. Once contraction stabilizes, it becomes largely irreversible because the surrounding proteins lock the new shape in place. In normal acute wounds, these cells do their job and then quiet down. In problematic scars, they remain active far longer than they should, contributing to raised, tight, or disfiguring tissue.
What the Scar Looks Like Over Time
A fresh scar typically appears pink or red because of the dense network of new blood vessels that formed during healing. Over roughly 12 months, those blood vessels regress and the redness fades significantly. The scar gradually softens, flattens, and lightens in color.
Most scars reach their final appearance somewhere between 6 and 18 months after the wound closes. This is why surgeons generally wait at least 12 to 18 months before considering scar revision: the tissue is still actively changing before that point, and what looks concerning at three months may look considerably better at one year.
Factors That Determine Scar Severity
Not all deep wounds produce the same kind of scar. Several variables influence the final result:
- Wound depth and type of injury: Deeper wounds that destroy more of the skin’s structural layers produce more prominent scars because there is more tissue to replace.
- Location on the body: Areas with high skin tension, like joints and the chest, tend to develop thicker scars. Wounds that run across natural skin tension lines also heal with wider scars.
- Skin tone: People with darker skin are more prone to raised, overactive scars.
- Age and nutrition: Younger skin tends to produce more collagen (sometimes too much), while poor nutritional status can slow healing and worsen outcomes.
Hypertrophic Scars vs. Keloids
When the remodeling process overproduces collagen, the result is a raised scar. The two main types look similar but behave very differently.
Hypertrophic scars stay within the borders of the original wound. They can appear within a month of injury but typically begin to flatten and soften after about six months. If surgically removed, they have a relatively low chance of returning. They are common across all skin tones and tend to form on surfaces where skin stretches, like over joints.
Keloids, by contrast, grow beyond the edges of the original wound into surrounding healthy skin. They usually appear around three months after injury and continue to grow without improving on their own. Keloids have a strong genetic component, occur most often in people with darker skin, and favor certain body areas: earlobes, shoulders, the chest, upper back, and cheeks. They have a high recurrence rate after removal, making them considerably harder to manage. Under a microscope, their collagen fibers are arranged in a random, swirling pattern rather than the orderly parallel pattern seen in normal scars and hypertrophic scars.
Sensation Changes in Scarred Tissue
Deep wounds often damage the small nerve endings in the skin. As the tissue heals, nerves attempt to regrow into the scarred area, but they rarely reconnect to the exact sensory receptors they originally served. The result is often altered sensation: numbness, tingling, hypersensitivity, or a strange phenomenon where touch in one spot feels like it’s coming from somewhere else. Some sensation may return over months to years, but deep scars frequently retain at least some permanent sensory changes because the misrouted nerve fibers continue to misinterpret signals.
Managing Scars During the Remodeling Window
Because the remodeling phase lasts up to a year or more, there is a meaningful window to influence how a scar matures. Silicone-based products, available as sheets or topical gels, are the internationally recommended first-line approach. They work by keeping the scar surface hydrated and occluded, which appears to calm overactive scar cells and normalize collagen production. For best results, silicone therapy needs to be used consistently for 6 to 12 months.
Keeping the scar protected from sun exposure during this period also matters, since UV radiation can darken healing tissue and make the scar more visible long-term. Gentle massage and moisturizing help maintain flexibility as the collagen network stiffens. The key insight is that the scar is not “done” when the wound closes. The months that follow are when the tissue is most responsive to intervention, and the choices you make during that window have the greatest impact on the scar’s final appearance and texture.