Ichy red small bumps on my neck?

i have a pretty larg rash on the front of my neck it is raised a little and has small ichy bumps . i have gone to my Dr and she gave me hydrocortisone .but when i put the cream on i was over come with a vary bad stinging pain it was unbarable and i had to wash it off .i have since tryed putting another unsented cream on the rash it does not sting but does not seem to be helping the rash ...any idea what may be causing this ?