Bruised skin does not really require much treatment unless bruising is particularly severe or infection has set in. Depending on how you got the bruises, there may also be a risk of some internal injury, so this should always be considered and ruled out before assuming that the bruise is the only injury that needs to be treated. Also, a mysterious bruise that appears on its own, without any apparent cause should be investigated, as it may indicate some serious illness. If this is the case, you should visit a doctor immediately, without any delay.
The best first aid treatment for a bruise is ice — for the first day, you can apply an ice pack several times through the day. This will ease the pain, minimize the swelling, and reduce the amount of blood that collects in the area. After applying the first ice pack, you should also clean the bruise thoroughly but gently, to prevent any infection from setting in. For the first few days, you should also rest as much as possible, particularly if the injury is to a limb. If possible, you should also elevate the bruised area, in order to prevent blood from pooling and causing more swelling.
answered by M W