Risk of syphilis from a french kiss with a woman? happened on 24th feb & 8th march (kissing only, no sex either time). she tested neg on 28th feb but her partner may have been cheating. i've red patches on tongue that come and go. geographic tongue?

Transmission of an infection is not possible if the microbe was not there to begin with. Regardless of what her partner was doing, if she had a standardized test and was negative, she could not transmit the microbe she does not have. There are many causes to a geographic pattern on the tongue.

You're probably the same person who asked this on a different medical forum. Little or no risk both because there is little chance this woman has syphilis; kissing can transmit syphilis but very rarely; and geographic tongue or red patches would rarely be the only syphilis symptoms. But feel free to be (re)tested if you remain concerned despite the reasoned, science-based advice you have had.