Culture negative but have cold sores and spit on vagina with a cut. now there is tingling & burning for 3 months in vag and butt. could it have spread?

Yes: 25% of people in this country have herpes, but 90% don't know it. A blood test would be better than a viral culture. If you have herpes simplex i (2/3 are oral) then this is a very common problem -- cold sores. If you have hsv ii (2/3 are genital), then you may have more prolonged/painful lesions that require valtrex/acyclovir treatment. Herpes is forever. This blood test tells you your history.

Yes: I would have it re-cultured. See another gyn and get a fresh opinion. May need a biopsy and more thorough testing. There are many infections which are hard to detect. May want to have course of several antibiotics to cover most of them. 2 gm of zithromax, Doxycycline 100mg 2 x a day for 2 weeks, maybe even add metronidazole. This will cover most things. Still may be herpes.