Hurt -
I know this may sound gross but you can use Vagisil or Athlete's Foot cream. They are both yeast infections like thrush and the medications are all pretty much the same only marketed differently. A pharmacist friend of mine explained this to me and told me to stop wasting money on vaginal yeast infection meds and use the Athlete Foot ones instead - much cheaper. Of course since your child does put his mouth on the area you would use it I would double check w/doc, nurse, pharmacist.
Just an idea I thought may be worth sharing. . .

Married 10 years Three Children: Son(8),Daughter(6),Daughter(3) DDay - May 6, 2004 False Recovery Begins - June 1, 2004 OW Pregnancy Revealed - June 27, 2004 False Recovery #2 Begins - August 30, 2004 OC born Feb. 25, 2005 Have chosen to have C DDay AGAIN -- June 10,2005 - Found out contact w/OW had continued from Sept-Feb Recovery Begins (again - let's hope it is real this time) July, 2005 C w/OC on indefinite hold while M is worked on