Went from a Rash to many pimples in one day?

Question

I was putting drywall on the ceiling in a very hot humid basement and the next day I woke up with a very large red rash covering my chest, shoulders and upper back. The pharmasist recomended cortozone cream so i applied that and the rash went away by day 2 but turned into either many small pimples or blisters. Could this be heat rash or an allergic reaction to drywall dust. To my knowlege im not allergic to anything. What can i do to get rid of all these blisters/ pimples?

Answer 1

you should stop the applicationn of cortisone

these pimples are due to the application of cortisone

cortisone shouldn't be applied over inflamed skin ,it just can be applied over very mild inflammation  

Answer 2

Try an antihistamine from the drug store.