depending on how infested you could clean it with peroxide and put antibiotic ointment on it. if it is red and swollen and hot to the touch or you are running a fever you should go to the doctor. he would treat it much the same way but with better antibiotics and probably prescribe antibiotics. he may do nothing, he may send you for a mental health evaluation to see if you are a danger to yourself, or he may evaluate you himself to see if you are a further danger to yourself.