My son is 6 y/0 started with what look like bug bite last evening on his knees and hands. I put calamine lotion on. Today they are spreading all over body. Back, underwear line, axilla, behind ears, buttocks, knees, legs, hands, face, wrists and chest. They seem to be move hive like and some look like welts. They are itchy at times but other times he says they aren't. I gave him one dose 25 mg po benadryl. No new foods or soaps. He is 11 days post op t/a. Antibiotics done 3 days ago? Any help?