I just got my lip pierced a week ago and my piercer told me that I only had to wait 2 weeks. But in 6 days, I've kissed (both 'french' and regular) someone all but 2 of the days and nothing has happened. The spot is a little tender, but as soon as we're "done" I use non-alcoholic mouthwash and everything seems to be fine. Of course, the fact that the piercing gets moved around a bit while kissing will probably delay healing, but so far, no signs of infection.
well i have had mine done about 5 months, and i was kissing about an hour after i got it done, it kindof hurt because he kept playing with it but other then that it was fine