I'm pretty positive CJ has thrush

- he has these white patches on the inside of his lips. I called his pedi, she said its not an emergency, but to bring him in on monday. She mentioned an OTC treatment -
Gentian Violet.
Has anyone used this before? The label on the bottle says it's for external use only. If swallowed, get medical attention. So it is NOT ok to use on his lips?? Or is it??
Or should I just wait until monday so he can get a prescription? It doesn't seem to bother him, but still...
Sigh.. why is it that whenever he has issues, it's ALWAYS on a friday, a holiday or when his pedi is out of town? It never fails..