Internal vs External Scar Tissue: How They Form and Heal Differently?

Scar tissue is a natural and essential part of the body’s healing process (1). When the skin or deeper tissues are cut or damaged during surgery or an injury, the body repairs the area by producing collagen. This new collagen helps close the wound and restore strength.

However, scar tissue does not always form in the same place.

Some scars develop on the surface of the skin and are visible. Others form deeper inside the body, where they cannot be seen but may still affect comfort, movement, and overall recovery after surgery.

Let’s understand the difference between internal and external scar tissue so you know what to expect during the healing process, including how each type forms and heals.

What Is Scar Tissue?

Scar tissue forms when the body repairs damaged skin, muscle, or connective tissue. After injury or surgery, the body moves through three primary healing phases (2):

1. Inflammation – Blood clotting begins, and immune cells clean the wound.
2. Proliferation – New tissue and collagen fibers are produced.
3. Remodeling – Collagen reorganizes and strengthens over weeks to months.

Scar tissue is primarily made of collagen. These collagen fibers are arranged in a dense, less flexible pattern. This is why scars often feel firmer than the surrounding tissue.

External Scar Tissue

External scar tissue is the visible tissue that forms on the surface of the skin after an injury, surgery, burn, or other damage to the skin layers. It is part of the body’s natural repair mechanism and develops when the skin replaces damaged tissue with newly produced collagen fibers. These scars can vary widely in size, texture, and visibility depending on the depth of the injury, the location on the body, and how the wound heals.

How External Scars Form?

When the skin is cut, the body immediately activates the wound-healing process. First, blood clotting occurs to stop bleeding. Then, immune cells move into the area to remove bacteria and damaged tissue. This stage is followed by the repair phase, where specialized cells called fibroblasts begin producing collagen (3).

Collagen is the main structural protein responsible for closing and strengthening the wound. In early healing, this collagen is laid down quickly and in a disorganized pattern. Because of this rapid buildup, the scar may appear red or pink due to increased blood flow, slightly raised due to excess collagen production, and firm to the touch.

As healing progresses into the remodeling phase, collagen fibers gradually reorganize and align more evenly. This process can take several months. In most cases, the scar slowly flattens, softens, and becomes lighter in color.

However, if collagen production remains elevated or the inflammatory response is prolonged, the scar may become:

• Hypertrophic (raised but confined to the incision area)
• Keloid (extends beyond the original wound boundary)
• Thickened or darker than the surrounding skin

The way external scars form and mature depends on factors such as incision tension, infection risk, genetics, skin type, and post-surgical care.

Timelines of External Scars Healing:

External scars typically go through visible stages:

• 0–2 weeks: Redness and swelling
• 2–6 weeks: Collagen builds, scar may look thicker
• 2–6 months: Gradual softening and lightening
• Up to 1 year or more: Continued remodeling

Collagen vs. Collagen Peptides: Which Is Best for Scar Healing?

Internal Scar Tissue

Internal scar tissue develops beneath the skin, within muscles, fascia, or around organs. It is not visible, but a normal part of healing after many surgeries.

Internal scar tissue commonly develops after abdominal surgery, liposuction, C-sections, orthopedic procedures, and injuries that affect muscles or connective tissue. 

How Internal Scar Tissue Forms?

Internal scar tissue forms in deeper structures such as muscle, fascia, or around organs after surgery or injury. Unlike surface wounds that involve a single skin layer, internal healing occurs across multiple tissue planes that normally move and glide independently.

During repair, the body produces collagen to reconnect and stabilize these layers. Because several structures are involved, collagen may form between adjacent tissues. If healing occurs too tightly or inflammation is prolonged, these layers can bind together, leading to fibrous bands known as adhesions.

Internal scar development is also influenced by swelling, internal pressure, and limited movement during recovery. These factors can affect how collagen organizes and how flexible the tissue becomes over time.

Do Internal and External Scar Tissues Heal Differently?

Although both types of scar tissue remodel over time, the way they are supported during recovery differs.

Internal scar tissue healing depends largely on systemic factors. Because it forms in deeper tissues, recovery is influenced by overall inflammation levels, adequate protein intake, micronutrient status, and gradual return to movement. The body requires sufficient amino acids, vitamin C, zinc, and other nutrients to organize collagen properly. 

Possible sensations during internal scar healing:

• Tightness
• Pulling
• Mild stiffness
• Temporary limited range of motion

To support your body internally with nutrition during surgery recovery, take HealFast Supplements. These formulations are formulated to provide key nutrients involved in tissue repair, including protein, essential amino acids, vitamins, and minerals. 

Check out this video where Jillian Tremaine shares her personal experience using HealFast pre-op and post-op supplements during her breast augmentation recovery and explains how nutritional preparation helped support her healing process.

External scar healing, on the other hand, can be directly managed at the skin level. Once the incision has fully closed, silicone-based scar sheets or gels are commonly used to help regulate moisture and reduce excessive scar thickening. Sun protection and proper wound care also play an important role in improving the scar appearance.

Related Articles:

Is Redness Around a Surgical Incision Normal or a Sign of Infection?

Which Nutrient is Needed for Tissue Growth and Repair After Surgery?

Dos and Don’ts for Scar Care After Surgery

Differences Between Internal and External Scar Tissue

FAQs

Q 1: Are adhesions common after surgery?

Adhesions are relatively common after abdominal and pelvic surgeries. In many cases, they are mild and do not cause noticeable symptoms. However, some individuals may experience discomfort depending on the location and extent of the scar tissue.

Q 2: Can internal scar tissue cause pain months after surgery?

In some cases, yes. As internal tissues continue to remodel, areas of dense or less flexible collagen may create sensations of tightness, pulling, or discomfort,  particularly during stretching, twisting, or increased physical activity. However, it’s important to understand that not all lingering post-surgical pain is related to scar tissue. 

Q 3: Can massage help scar tissue heal?

For external scars, gently massaging with scar creams (once fully healed) may help improve flexibility and circulation. For internal scar tissue, guided movement and physical therapy may support mobility. Always seek professional guidance before beginning any scar management technique.

References: 

1. Wikipedia contributors. (n.d.). Scar. Wikipedia. https://en.wikipedia.org/wiki/Scar

2. National Center for Biotechnology Information. (2023). Wound healing and repair. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK586083/

3. Fibroblast.org. (n.d.). Scar formation. https://fibroblast.org/scar-formation/