Yellow label symptoms and conditions

I am on two 500 mg doses of cephalexin daily to help heal a bug bite..Still waiting for the biopsy to come back. Doctor suggested could be a brown spider bite. Definitely want to stop the skin deterioration and get the wound from where the bite was removed healed but the itching started on day 3 on my stomach and has now spread to entire torso, back, insides of arms and legs. I have tried aveeno baths, benadryl (knocks me out) and eucerin itch-relief. Today I coated my entire body with 1% hydrocortisone with little relief. HELP - I am scratching to the point of bleeding and now that I have read these other comments will NOT take another one of these pills. Any other OTC relief anyone has found?