<s>[INST] My father has had a lump behind his right ear for awhile now. His dr said it was nothing. A couple days ago he touched it and was almost greasy feeling and stunk bad. I thought it was just grease from his hair. He just a moment ago pushed on it and a HUGE glob of whiteish pus came flying out. Any ideas? [/INST] Hello!Thank you for the query.From your description, for sure it is nothing serious. Most likely it is a kind of benign skin lesion like sebaceous cyst or pimple like lump. Pus presence in it indicates some kind of infection. Luckily, pus drainage is the right treatment for it. So if it has been completely drained, all you need to do is to have it under observation. If it will regrow, please consult a surgeon.Hope this will help.Regards. </s>