I personally wouldn't apply tea tree oil to the vagina as it can really burn. I would watch what I eat, take necessary probiotics as well as consider consuming cfort10 internally. It worked really well for me.
I'd also use something that is safe to wash my vaginal area with, always making sure it's dry, especially now that it is starting to get warmer.
But in general I would be careful what I apply to my vaginal area, maybe a mild tea tree oil solution mixed with coconut oil would be better / safer. If you ever feel any sort of burn rinse it off immediately.