I have no interest in him whatsoever but he kept slowly moving his hand up my arm really awkwardly and saying awkward things during a movie we were watching and he kept just staring at me and trying to get me to look at him and I didn't know what to do so I just made out with him so he would stop being weird.
He may or may not think we're dating now.
He's a fucking idiot.
I realize how this may sound bad but in my defence, he was really really awkward and freaking me out and I didn't really have a way out of the situation other than that
You say he's the idiot but I mean, you can't really blame him for thinking you're interested seeing as how you chose to handle his awkwardness and your lack of interest in him by making out, and not stopping his hand from wandering.
Just tell him that you're flattered, but not interested. The longer you lead him on, the more awkward it'll be when you eventually tell him the truth.
That is literally the exact opposite of what you should have done. If you felt uncomfortable you could have left or told him to stop or move your body away from him. Anything other than act like you are into him.