This one makes me laugh. It’s an altogether very serious subject depending on what actually happened, but it still makes me laugh.
Considering how little is here, there really isn’t a lot that we know about this situation. We don’t know the gender of either person talking nor do we know their age or how long they have known each other or what their relationship is outside of this exchange beyond the fact that it almost definitely does not include kissing as a normal event.
The first thing that I can infer from this, other than kissing is not normal between these two, is that the speaker does not have a clear memory of what happened. That leads to wondering why. Is it something normal like being over tired or over indulging in alcohol or even some sort of drug? Or is it something much less normal like a spell or a fantasy type drug?
The next question is, what is their relationship? It’s possible that they used to be on kissing terms and something happened to make one of them forget and now they are slowly remembering. It’s also possible that they are friends only or even complete strangers and this is just too weird to contemplate for the one who is speaking.
There is also the possibility that the kiss in question was not one of lovers, but instead something else such as a kiss on the cheek or forehead, something that is still odd for the character to consider given their relationship. In such a case, it could turn out that they are siblings or parent and child.
Stories that deal in forgotten memories can be tricky since you need to keep track of not only what they do know, but also what they should and yet do not know. Do you like stories about forgotten memories? If you do, what’s your favorite?