Was prescribed DS (Double strength) 800-160 Sulfameth/Trimeth for...

Was prescribed DS (Double strength) 800-160 Sulfameth/Trimeth for 7 days/ 2 pills per day to treat a staph infection from a cut. On the last day, I woke up with a swollen gland under my left ear and a red, itchy rash all over my face and arms. Small hives also began to appear. Today is the next day and the hives are spreading but don't last very long. Very itchy, though, and that's unrelenting. Hoping it will decrease quickly since the first symptoms didn't appear till the dose of Bactrim was almost over.