Allergic reaction to a HOT TUB!!!?

I was in my friends hot tub last night. I just got out of the bath tub today and i have a lot of little red bumps on my chest and back. another friend got this same reaction about 2 years ago from the SAME HOT TUB. she had it severely all over her body and had to get steroids from the derm. to fix it. what should i do to help it go away? should i put cortizone on it or something? it dosen't itch. and they use bromine in the hot tub if that makes a difference.