dont use ice. take some heinz vinegar and a cotton ball and soak it with it. then place the ball where the bruise is and keep it on for an hour. should significantly reduce the color and make it heal faster. if u dont believe me, ask Cory Harvey. worked for him and always works for me =)
It does actually work. Swelling is caused by blood vessels filling up with blood and ice constricts the blood vessels to help keep swelling down, but it will only help for minor swelling, it shouldn't make that much difference for major swelling.
you should never use ice on a lump on ur head this can stop the swelling on the outside and force the pressure to build on the inside instead.
The swelling is a form of defense and is formed by the heat given off. the ice cools it down and makes the swelling go down.
I only have apple cider vinegar. O.o