Hi J.,
There could be many culprits. I agree with Colleen, it's probably yeast. Candida is rampant in our society today because of all the sugar in our diet, whether it be processed sugar, white potatoes, white flour pastas, etc. You get the idea...what most kids eat these days. And if it is yeast, the amoxicillin has made it worse. Antibiotics CAUSE yeast. (If you HAVE to give an antibiotic, ALWAYS add acidophilus to prevent yeast.) If yeast is in the vaginal canal, then her whole body is eaten up with it. That is the LAST place it shows. Remove the sugar completely and add plain yogurt with active cultures. If you can afford it, Tanalbit is the best solution and it will rid the entire body within 3 months.
My 15 year old had a problem like this and I sat her in a bath of a solution that I can tell you about. It has melaleuca oil in it. Yes, bubble baths are BAD, but this is not that. If you want more info, please let me know.
Regards,
M.