First kiss with a guy

So a couple of days ago I kissed a guy that I have been talking to for a while and it wasn’t good! We were out of sync and he was kissing too fast and I felt his teeth! It wasn’t a good experience but I don’t know how to slow it down and make it more romantic! It was also his first kiss. Do I say something to him? If so what? What do I do? Has this ever happens to you before?