Dang, I thought this was one of those teaser thread starters, looks like I was wrong.
I recently was criticized on the Mech/Maint board for recommending that the best place to start for a high temp. gauge reading/overheating issue, was to replace the thermostat. With that in mind, I'm not going to touch this with....ahh probably not a good metaphor here.
Seriously though, from the description, it does sound very similar to a yeast infection. These days the medication (eg. Monistat) that used to be prescription is now OTC. If there was burning on urination, it could be a urinary tract infection, which is also quite common, but a doctor is required to treat that.
(Disclaimer) That said, I'm not a doctor nor do I do play one on TV. So, if the Monistat does not work in reasonable time (as directed), she needs to see a physician. Convincing her to see a doctor sooner rather than later, would be the best idea.