I have oral herpes. If I kiss a guy and we get kinky then he starts eating/licking me out, what are the chances that I can get genital herpes?

It is possible . You can transmit type 1 herpes virus to genitalia and it will cause genital herpes by herpes type 1 virus.
Always there. If you have an active lesion you can have spread to the genital region. If not active it is stil possible but less likely. Also the person that you are doing this with -what is his herpes status? All these factors come into play. Nothing however is for sure. The chances of spreading oral herpes virus to the genitals is much less than spreading genital herpes.