Personally if I still punted, I would refrain from kissing, and RO. But that would affect the quality of the punt, so I think I would abstain until the cold sore has gone.
Having said that, on the flip side, in my early days of punting, I punted with a WG, who refused to kiss me because she said she had an infection in her mouth, but still charged me her full rate. I didn't make a deal out of it as I obviously didn't want to run any risks.