Red ring around my 10 year olds lips?

This has been happening for over 4 years. Doctors says stop licking his lips he gets teased at school I put antbactirail ointment it work at first the he bilt a resistance to it what is it . What do I do it comes on ever other month I'm tired of it. Is there a cure ?is it a rare form of ring worm or a form of staph.. tea tree oil doesn't work any more eather