I have only gotten hives once (it was something I ate, so it was a severe case), but I had to go to the hospital and they gave me a shot. Each time my mom has gotten them, we also have to take her to the hospital. It took like 5 minutes for them to give me a shot, and I was done.
Oh the chicken pox. Wow! I hope that you feel better. I had them when I was in second or third grade. They were awful. The calamine lotion and oatmeal baths help. Don't scratch or you will have permanent scars. Wear cotton gloves and cut your nails short if you need to. I hope that you feel better.
Actually regular old oatmeal will work in a bath, throw in a cup or two depending on how big your tub is. Soak 30 mins or so and it will help sooth the skin. And do take the benadryl. This will help if it's an allergic rection. If it is chicken pox, theres not much you can do, just be happy it's not shingles or hope it doesn't turn into that.