B.A.
With my older daughter we had thrush for 5 months - the only thing that worked finally (and kept the pain down until it was gone) was Grapefruit Seed Extract diluted in distilled water. The GSE is pretty pricey, but it needs to be diluted quite a bit (10-30 drops in an ounce of water) and I just used a Q-tip dipped in the solution on each nipple before and after each feeding and on her mouth a few times a day.
It worked very well and better than anything else we tried!
Best wishes! Thrush is rough :(
~B.