Suggest Treatment For Blisters On Wrist With Itching And Paining

i have had some blisters pop up on my wrist and they continue to get bigger and bigger and my doctor isnt sure what it is now. he thought it was mrsa but nothing he gives me seems to help they continue to grow, it is very painful at times sending pain up my arm, burning, itching, and stinging. can you please help me figure out what I am dealing with?