Finally turns yellow-brown or light brown before disappearing completely. First Aid & Treatment Bruise healing - series—Healing, part 2 - MedlinePlus
A bruise (contusion) is a common skin injury that occurs when small blood vessels (capillaries) under the skin break and leak blood into the surrounding tissue. Because the skin itself is not broken, this trapped blood pools and creates the visible discoloration we recognize as a "black and blue" mark. Bruises
Initially red or pinkish immediately after the injury; it quickly turns dark blue, purple, or black as the blood loses oxygen. Initially red or pinkish immediately after the injury;
As your body repairs the injury, it breaks down and reabsorbs the trapped blood. This biochemical process causes the bruise to change colors over roughly two weeks: it quickly turns dark blue
It fades to a green or yellow hue as the body breaks down hemoglobin into other compounds.