Dear L.,
Try organic coconut oil on the rash! Apply it sparingly several times a day, and I'll bet the rash will be history within a week or less. The best thing is that it's safe to consume, so you don't have to worry about your daughter licking it.
It's easy to find in the natural foods section of most groceries, right next to the organic cooking oils. It's in a jar that looks like a mayonaisse jar, and it only costs about $5.50 for a 14 oz. jar. The brand I buy is called Spectrum.
Coconut oil has natural antibiotic, antibacterial, and antimicrobial properties.
I used it recently on the rash caused by shingles, and it cleared it up right away. I can't tell you what a miracle this stuff is! Do a search on the 'net for "The Coconut Oil Miracle." It's a book by Bruce Fife, and it's full of terrific information.
Good luck!