Is this a hit and run and can I get in trouble for it?

Alright, so I was pulling into a gas station and its wet/snowy/icy. I go to brake and dont stop in time and barely knick the side of a car. There are two scratches on the side of it that are white, literally just clear coat that got scratched that anyone can wipe off to make it look like it never happened, and/or use rubbing compound to make it look brand new. Anyways, I knew I hit him, he comes over to ask for my info, we exchange info, I apologize and we shake hands. I see him get in his car and watch him pullout, so I do the same. My cousin just said that if the guy was a real he could just turn around, go back to the gas station, call the cops (as he has my license plate #) and say it was a hit and run. Can he do that? Was it illegal for me to pull away? If so, what would i get charged with and what do you think I would get? Fines?