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As your genital contact is a protected one, you are unlikely to get a STD on your genitals. The possibility of vaginitis due to previous contacts can not be ruled out.HPV infection
either in oral cavity or with genitals would unlikely to produce any burning sensations.
As you had unprotected oral sex Herpes simplex
infection, gonococcal and Chlamydial pharyngitis
have to be ruled out with examinations and appropriate investigations.
Vaginal burning may also be due to phobia towards STD.