I have a house guest who is currently on Prednesone for a skin problem of unknown origin, He is a controlled diabetic. His skin rashes have completely gone away until today (30 mg. dose today of Prednesone) when he noticed a small round spot on the inside area of his elbow. It appears as a dark outlined red circle with a slash through it. It is a bit raised to the touch. Do you think he should see a dermatologist?