My teacher kissed my cheek..

I was in my geology class and I completely forgot about a test we had, and the day came to take it and I totally bombed it, didn't know any of the answers. When my teacher gave back the tests after grading he asked me if I would like to redo mine, and I gratefully said yes. I decided to go out and put a little gift bag for him - a chocolate bar, a cookie, mints, and a granola bar, a little snack bag since he teaches two 3 hr long classes in a row. Plus I dunno I've always thought teachers like little gifts that show appreciation for them! My college teachers rarely ever let students retake tests. 
So, the next class after it ends there's a room right behind the classroom that they store the rocks in and microscopes and he went right in there after class ended. I followed and I was like hey, I have something for you and I gave him the snack bag. He was like oh thank you this is great sometimes I get hungry and he hugged me, and then as we were breaking away from the hug he stopped and slightly pulled me closer to kiss my cheek....... this was really weird for me. I really don't know how to feel about this, it feels like I was touched by an alien. It feels like he has less professional student-teacher feelings for me and that creeps me out. I don't really know how to handle this 
Edit: I'm not going to ruin his career, I promise. I think my school wouldn't see it as a big deal anyways. It just makes me feel weird, the moment felt semi intimate because he got so close to me and that makes me so uncomfortable. Before I gave him the gift, he did look at me sweetly and say "hey ___ what's up?" And touched my arm. Maybe I should have read those signals and just gave the gift and abruptly left. I feel like him, someone as old as my dad wanted to kiss me on the lips