I have what I thought was mosquito bites on my arms but these bites have become much worse over the last few weeks. It started with what seemed like a heat rash on my fingers, small blisters, very itchy fingers. Then what appeared like big mosquito bites on my arms. Not responding to Benadryl. Now I have bumps appearing on my hands and fingers, one or two at a time each day. Very itchy. Small blisters in the middle as they appear. I have not noticed any mosquitos and have not spent a lot of time outside in the last two weeks. The welts appear only on my arms, hands, and fingers.