How long does it usually take for a bruise to apperar?

It depends on the depth of the injury. If you are injured very deep, the bruise may appear several days later and already appear to be fading to yellow. If it is a shallow bruise it can appear almost immediately. The longer it takes for the blood to reach the outer surface the deeper the bruise. For the bruise to heal, the body must reabsorb all of that blood, which, depending on the severity could take days or weeks. A bruise is caused by the spillage of blood from the vessels. The colors have to do with the change in the blood as it's broken down and re-absorbed by the body. At first, bruises may appear red, then turn blue or dark purple within a few hours, then yellow or green as it heals.

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