My husband had a boil type blister on his leg. It popped and now it is getting bigger and had red around it with a discharge. The top of the scab which is about the size of a silver dollar is dark. He has been feeling cold for the last 3 days despite 100 plus weather. He has an appointment with a gastro doctor for ulcerative colitis and he also has gout with very little pain. Is there a way to tell if the wound is a bite or MRSA like my nephew had. It is hard to tell the difference from what I have seen.