Hi Doctor, my 10 year old son was in a collision with another child, in the playground 5 weeks ago, which resulted in a bruised cheek and a moderate concussion . He s well and the bruising has almost completely gone but he s left with a pea sized lump where the bruising used to be. The lump is a little sore to touch. Does the lump need to be looked at by a doctor for treatment or will it gradually heal by itself? Thanks very much.