How To Get Rid Of Rash On Upper Arm Completely?

Hi! I've had a rash on my upper arm for several months now - it does not itch and hasn't spread beneath the fold in my arm. I've tried cortisone creams but nothing seems to work to get rid of it. It almost looks like small blisters that have no fluid and looks awful. People give me strange looks and have asked if it's contagious. Obviously, it isn't as it hasn't really spread. I'm 65 and had the shingles shot when I was 60. Is there anything I can do to help this fade away, or get rid of it completely? Thank you...........