Man with visible facial<unk> s. All<unk> ring is composed of the same collagen as the tissue it has replaced, but the composition of the<unk>  tissue, compared to the normal tissue, is different.<unk>  tissue also lacks elasticity unlike normal tissue which distributes fiber elasticity.<unk> s differ in the amounts of collagen overexpressed. Labels have been applied to the differences in overexpression. Two of the most common types are hypertrophic and keloid<unk> ring, both of which experience excessive stiff collagen bundled growth overextending the tissue, blocking off regeneration of tissues. Another form is atrophic<unk> ring (sunken<unk> ring), which also has an overexpression of collagen blocking regeneration. This<unk>  type is sunken, because the collagen bundles do not overextend the tissue. Stretch marks (striae) are regarded as<unk> s by some. High melanin levels and either African or Asian ancestry may make adverse<unk> ring more noticeable. Hypertrophic Hypertrophic<unk> s occur when the body overproduces collagen, which causes the<unk>  to be raised above the surrounding skin. Hypertrophic<unk> s take the form of a red raised lump on the skin for lighter pigmented skin and the form of dark brown for darker pigmented skin. They usually occur within 4 to 8 weeks following wound infection or wound closure with excess tension and/or other traumatic skin injuries. Keloid Keloid<unk> s are a more serious form of excessive<unk> ring, because they can grow indefinitely into large, tumorous (although benign) neoplasms. Hypertrophic<unk> s are often distinguished from keloid<unk> s by their lack of growth outside the original wound area, but this commonly taught distinction can lead to confusion. Keloid<unk> s can occur on anyone, but they are most common in dark-skinned people. They can be caused by surgery, accident, acne or, sometimes, body piercings. In some people, keloid<unk> s form spontaneously. Although they can be a cosmetic problem, keloid<unk> s are only inert masses of collagen and therefore completely harmless and not cancerous. However, they can be itchy or painful in some individuals. They tend to be most common on the shoulders and chest. Hypertrophic<unk> s and keloids tend to be more common in wounds closed by secondary intention. Surgical removal of keloid is risky and may exacerbate the condition and worsening of the keloid. Atrophic An atrophic<unk>  takes the form of a sunken recess in the skin, which has a pitted appearance. These are caused when underlying structures supporting the skin, such as fat or muscle, are lost. This type of<unk> ring is often associated with acne, chickenpox, other diseases (especially Staphylococcus infection), surgery, certain insect and spider bites, or accidents. It can also be caused by a genetic connective tissue disorder, such as Ehlers–Danlos syndrome. Stretch marks Stretch marks (technically called striae) are also a form of<unk> ring. These are caused when the skin is stretched rapidly (for instance during pregnancy, significant weight gain, or adolescent growth spurts), or when skin is put under tension during the healing process (usually near joints). This type of<unk>  usually improves in appearance after a few years. Elevated corticosteroid levels are implicated in striae development. Umbilical Humans and other placental mammals have an umbilical<unk>  (commonly referred to as a navel) which starts to heal when the umbilical cord is cut after birth. Egg-laying animals have an umbilical<unk>  which, depending on the species, may remain visible for life or disappear within a few days after birth.
Scar
Edema blister
Burn 
Burn
Edema
Injection fibrosis
Heat edema
Oscar 