It could be fungus, chafing, psoriasis, or one of a few other non-serious but annoying conditions. I suggest you show it to a doctor. Meantime, you can use the Lotrimin--I am reasonably sure it has just made it temporarily redder, not worse. Whether or not you respond to it will make it easier for the doctor you see to tell what it is and what to do about it.
Best.
Dr. Rockoff
Look up "tinea versicolor" on a google search.
It can usually occur during the summer months, it is
a skin fungus. Good luck, sounds awful. Don't scratch.