I went to the urgent center yesterday because I noticed a bluish discolored swollen area on my forearm around lunch. I know I had scratched scabs there before due to dry skin I think and now there is a small line of openings In the skin. I thought maybe I scratched hard or something but was surprised at the color. I was already on the second day of Bactrim due to a UTI, so they said to take it for another day as I planned and prescribed a prescription ointment to apply 3 times a day. I have had a headache today ( possibly caffeine withdrawal) to help with the UTI. Headache is better tonight and area is more pale reddish brown and green. Swelling has gone down. I do feel a little warm but temp is only 99 degrees. Arm area may be slightly warm but hard to tell. I had cold shrimp for dinner a couple nights thawed from the frozen bag that said it was cooked. Is there any chance this could have something to do with flesh eating bacteria? Will this antibiotic be sufficient and should I be taking it longer than the 3 days.