I've Had A Rash For Over A Week. It Started

I've had a rash for over a week. It started with just a few small bumps between my breasts, I thought might be a bug bite. But they have now spread to my upper chest area. I went to my Dermatologist on Monday afternoon who prescribed Betamethasone Dipropionate.05%. This caused severe itching for which they then suggested an over the counter anit-itch cream. It is very painful and intensified if in the heat. The assured me it was not shingles (thank heaven). But, the Steroid cream does not seem to be having an impact. I'd like to know if or when I should be concerned about Sepsis? I don't have any other health conditions but this is concerning, and painful!