Hello, Yesterday I suddenly developed a extremely irritating rash around my neck and on my collar bones. After I got home and changed my chest and around my bra area became very itchy. I noticed red raised areas (no bumps yet) over by breasts around the areolas and definite marks under my bra area. It was isolated to these area. I took 25mg antihistamine and a warm shower and moisturized with coconut oil, this gave me enough relief to sleep.This afternoon the rash moved into my armpits, under my chin, onto my abdomen and still on my chest but lessened the severity.tonight I've noticed small blister like bumps under my right armpit and the rash spread to my shoulders and back as well as still on my chest and chin. Its extremely itchy and there's other bumps they sort of look like bites but chow up and recede with in the hour. Other bumps are larger, then there's areas that resemble eczema. I just want to know what it could be. I'm also using hydrocortizone cream 1% and it helps momentarily. Please help, I'm going crazy!25 year old, female, no known allergy's, Arkansas,usa.I have photos but I don't know how to upload them.

There are no doctors on this site, and even a doctor could only guess based on what you describe.

The only guess I have is a possible allergic reaction. Sadly no one online can give you an actual diagnosis. Best to see your doctor.