Hylands carries a brand of arnica spray that is a must have in a home where you have kids. Arnica is an herb that helps to prevent bruising. I recommend the spray for children and you can pick it up for about $7. You just want to be careful not to use it on broken skin, as the spray has alcohol in it and can be irritating or sting broken skin.
Last night my little boy smacked right into a hard wood corner with his forehead and started to bruise and swell right away. I applied a few sprays of arnica to his forehead immediately. The swelling was gone in a few hours and this morning he has only a small bruise. SO much better than it would have been! So, moms, keep a bottle handy and spray all those bumps and bruises!