Acne scars, hyperpigmented or pigmented scars, surgical scars, and keloids are the most common types of scars.
Compared with blackheads, inflamed pimples look like red bumps, pustules, nodules (larger red bumps), and cysts, which can leave scars if not squeezed. And these acne, if squeezed or improper "beauty therapy", are more likely to leave severe marks on the skin.
Pigmented scars on the legs are usually caused by a rash or insect bites. Among Asians, pigmentation is a normal response to skin damage. If you stop scratching, pigmentation may fade naturally.
As the name suggests, surgical scars are surgical operations such as lumpectomy and sutures after skin cuts.
Scars are usually limited to the injured area. Scars that exceed the scope of skin damage are called keloids. For example, vaccination is usually injected into the skin through a fine needle, but the keloids appearing at the injection site are larger than a pinhole wound. Keloids are mostly inherited from families.