I took trimethoprim for three days for a UTI. I developed a rash on my hands almost immediately. I finished the course six days ago and the rash has been getting steadily worse, and is now up my arms and legs. It doesn't hurt but looks awful. It's blotchy, and the skin on my hands is peeling in places. I know that a rash can be a side effect of the drug. I feel completely fine but I'm worried about this rash.