My 3 year old daughter hit her forehead on cornor of door. bid bump and instant bruise what should i do?

Ice it, if she'll : let you. Avoid warm water on it. If she had no laceration or loss of consciousness, there's not much else you can or need to do. The bruise may spread to more dependent areas, but a large bruise under the lining of the bone sometimes can't resorb enough to avoid local calcification, or a " hard lump" as it heals.

Ice and love: As long as the skin is intact, all you need to do is put cold compresses or ice pack on the area. Monitor for any symptoms such as severe headache, recurrent vomiting or her complaining she is seeing funny (visual disturbance). Otherwise, just giving her a big kiss on her head and cuddling with her and reading to her is good therapy.