S.C.
Please don't ever put steriod creams on a closed diaper area as one of the moms suggested. That is specifically what you should not do with those creams. And when using steriods (even over the counter) you should first see a doctor.
Second, it sounds like a yeast infection. So use the cream, after you see all the bumps go away, use it for another 3-5 days. Good luck.