Day 1 severely swollen face and lips given benedryl and sterroids. Day 3 hives on scalp body pain and itching?

Hives. Mostly due to an allergic reaction to a medication, newly used chemical such as shampoo, hair color, . ..., or a new food, like chocolate...... If you can recognize the "agent" avoid it and with the antihistamine and steroid your symptoms should go away otherwise need to get evaluated.