I started prednisone 15 mg yesterday for polymyalgia rheumatica. A couple of hours after taking the pill at 7:00 pm I developed a red rash on my upper chest and on the outer part of my right calf. I also was itchy and had a few disturbing mental images as I tried to sleep. At 3:30 am I woke to a vey brief hallucination (my first ever) and my tongue is swollen. I have also been on Buprorion for a few years, alternating 300 mg to 150 mg daily. Can I take Benadryl to reduce the rash and tongue swelling?