Most Helpful Guy
It's not easy for a guy to get over his friend kissing the girl he likes, so just give him some time. Talk to him face to face, tell him that you're sorry but you didn't reciprocated, it wasn't your fault.
Maybe he doesn't believe you, at first, but he'll eventually will if you are 100% honest and say it with your heart.
Don't text him every day, give him a little space. Like I said, talk to him face to face if you can, if not, text him and then wait like 2-3 days to text him again.