She told you. To me that means that, with a little work and some time, you'll be back to normal.
HOWEVER. You need to have a serious chat about what her feelings for this other guy actually are, and you have to make it clear that you don't share (if that's your angle), and that she needs to make her choice outright. Does she want you, or does she want this other guy? Make it clear that there are no half-measures, and move on, in whichever format that decisiton takes.
Whatever you do, don't get resentful over this. It was a kiss. And she told you about it.