Hello. About a week ago, a rash that looks to come from an allergy appeared on my arm. My doctors could not find what I was allergic to through multiple tests. However, that is not the concern. Beginning yesterday, the rash split at certain parts on my arm, revealing the skin underneath, and has been profusely leaking clear pus. I have no pain in my arm, and it is functional, however m still worried. What do I need to do to insure this recovery, and do I need to go to the doctor?