Scar tissue is a type of fibrous connective tissue that forms as a result of injury to an organ or body part. It is formed when collagen fibers begin to replace damaged tissues, creating a thickened area that helps to repair and strengthen the affected area. Scar tissue can be visible on the surface of the skin, appearing as a raised or discolored patch, but it can also form internally without being noticeable from the outside. While scar tissue is necessary for healing, in some cases it can cause problems such as restricted movement or pain if it forms excessively or in an abnormal location.