I really don't dig this guy. Whether you've done things before or not, for him to keep pressing you to do something after you've said you don't want to do it he's acting crass. What part of "no" does he not understand?
That said, you know now to not pretend to be anything you're not just to make someone like you. Cuz see then it's not you they're liking. It's the person you are pretending to be--a person who doesn't even exist.
Don't beat yourself over the head over what you've done. Just start where you are. If this guy rejects you after you've told him the truth you haven't lost much. If he makes a big deal about the fact that you lied, take the punishment and move on. That's all you can do. But don't do it again.