How Can A Leg Lump With Swelling And Bruising Be Treated?

hi my fiance has bangedthe front of his lower leg on our wooden bed last week the area has become red and he now has a bump on it.we have been using arnica cream to help bring out the bruising bwhich has helped the area around the lump but the lump is still red.do u think it could be infected?or do u think the lump is just swelling from the bang