Suggest Treatment For Rashes Under Breast And Legs

I have a rash under both of breast and between my legs for about 3 weeks now nothing I do seems to help its blister then goes into a very raw and itchy and painful areas. I have used creams powders diaper rash cream, I dont know what else to do I have an appointment with my Doctor on Tuesaday is there anything I can do now to get some relief?