bruise gradually changing color

Quick answer：

Bruising that gradually changes color is a common occurrence after minor injuries. It typically starts as a purple or blue color, then progresses to red, and finally turns green and yellow before fading. This color change is due to the body's natural healing process, where blood vessels break and leak blood into the surrounding tissues, causing inflammation and the subsequent color changes. The duration of the bruising can vary depending on the severity of the injury and individual factors.