I Am Allergic To Sulfa Medication. I Was Taking Them

I am allergic to sulfa medication. I was taking them for my acne. I had taken two antibiotics a day for ten days. At the end of day 10 I broke out in hives. I am now on allergy medication, day one, and I do not want to return to work with such noticeable hives all over my body. How long will it take for my hives to go away? And how do I flush sulfa out of my system?