A guy friend kissed me on the lips good bye, what does it mean?

Each year I make a Halloween party, my guy friend had said he wasn't coming this time because he had to work, but his sister was dying to come.

So when I saw him at the party I was very surprised and very happy, even though he had a costume and make up I recognized him immediately and hugged him. He was also happy to see me and until I hugged him and expressed my delight in his presence he hadn't recognized me.

He asked how I had known him immediately, even though no one else had been able to, but was very happy that I did recognize him. He jokingly said that if I wanted he could leave, because I had chastised him for telling me he wasn't coming.

During the party we danced a few times, and he noted I had improved my dancing.

At the end of the party, when he was leaving he came to say good bye, with his entourage, so first I said my good byes to his cousin and his sister.

When his turn came he hugged me tight said he had a great time that my costume had been great, kissed me on the cheek then hugged me again. Then he pulled apart a little, said he had a great time and that he values my friendship and the leaned towards me again and I thought he would hug me again when he surprised me by kissing me on the lips briefly.

I like him a lot, he's been a good friend and so I don't want to read to much into his gesture but it's driving me nuts.