When you are beated badly , why does yr skin turn blue-black on that area?

When you get a bruise or a other injury, your skin can turn black and blue. This happens because very small blood vessels which are called capillaries broke. Capillaries are the smallest of all your blood vessels, only visible under a microscope. When the capillaries break, this can cause bleeding inside your body which is called "internal bleeding."

it would be heredity