I always call the ped and she prescribes nystatin and it is betterwith in a day!
Mommyjeep11 also said something that works. Try the neosporin and cornstarch. It absorbs while the neosporin helps the bumps.
When my daughter would get diaper rash I would let her fall asleep and take her diaper off with a towel under her bottom just incase she had an accident. Let her "air out" as much as possible. Even try putting little underwear on her so the air can dry it up. It worked for me.
When my son would get bad diaper rash I would lay him outside in the sun for 10-15 minutes at a time several times a day and then when we came inside I would use neosporin with a thin layer of cornstarch on top. His rash would be gone in no time. Even did it when he had thrush one time. Everything the dr gave me would make it worse :/ I had to call my grandma and that's what she told me to do and it was like a miracle how quickly it would heal up.
Lanacane makes an antichafing gel that works great and it numbs the pain. I also use boudreauxs butt paste too. Good luck.
My son gets those rashes once in a while I use extra strength zincofax and it looks better in 3 hours. I swear by it or even something that's called Beaudreux's Butt Paste. But, if its as bad as I think I would try the zincofax first.
The best way to heal it is to let her skin breath. It may get a little messy without the diaper but it will be worth it. Desitin, but not the creamy type, the one that is really thick can help as well. Change the diapers often or maybe let her sleep without the diaper just put something to protect the sheets.
Bring her in to her Pedi. It could be a yeast infection...
not sure what they told you to do, but get some cortizone cream (store brand is fine and much cheaper) and then some nite time desitin (store brand as well) Trust me it works wonders!! I never learned this until my 3rd baby. Wish I would have known sooner. Hopefully it will go away for her little bottom I hate seeing them in pain. Also if you can let her go without a diaper like right after a BM, it will help with the air on it.
Triple paste is a life saver!!!!! My son gets rashes like that after eating blueberries. Its the only thing I've found that works. Within 24 hours the rash is usally gone!