my son is 31. the other day he thought he had a bite on his arm. after squeezing it pus came out. lots and lots of pus for several days. 3 days later his back hurt without straining it . arm got better back got better. now he has another (bite?) on his other arm. His back is hurting again... can you help me? Also first arm is pusy after knocking the scab off. He almost refuses to go to the doc.