What Causes Dry Skin And Blisters On Penis Leading To Pain During Sex?

So my boyfriend and I have had unprotected sex every night for a while now. But now we can t even do it at all because its hurts him very badly. It almost seems like dry skin and when we do have sex it irritates his skin and he gets like these little blister things, which are what is stinging I guess. How should I solve this? Or should he go to a doctor? It is a very painful thing for him. Please help.