Breaking out in little hives on face, neck, &chest for weekn a half. What could it be? Itchy! I break out, take Benadryl (diphenhydramine) n they go down, itch, then back.

See a dermatologist. It is difficult to make a proper diagnosis since I am not there to see the condition. I recommend seeing a dermatologist so that they can make a proper diagnosis and give you something to get rid of the condition or relieve symptoms.