Hello! I have been through your question. Related your concern I think the most probably diagnosis is scabies. You should know that scabies is a skin infestation caused by a very tiny mite known as the Sarcoptes scabiei, that can live on your skin for up to two months. Common sites for the rash in older children and adults include the,wrist, elbow, armpit, nipple, penis, buttocks, area between the fingers.The rash itself can consist of tiny blisters ( as you have) or pimple-like bumps. What I suggest for this situation is doing a physical examination by an Infection diseases specialist or dermatologist to define better the diagnosis and usually should start the treatment (with 5 percent permethrin cream or 25 percent benzyl benzoate lotion) that must apply all over the body. I hope my answer help you. I wish you a quick recovery.