How To Cure Pus Filled Lumps At The Top Of Head?

my husband is 33 and has a few lumps on the top of his head, he was shot in the face about 5 years ago and started getting one of them about a year later now he has about 5 they do hurt sometimes, in the cold weather they are more sensitive and they do puss sometimes also. what should we do and should we be really concerned (with out health insurnace it is hard to see a speacialist or get the labs done on the puss)