I need someone to know

My boyfriend hit me. I think. He punched me in the arm (during a very heated argument) while he was in the passenger seat of my car. It hurt a lot but he told me he didn’t even hit me but I think he did? He shouldn’t lay a hand on me at all right? Idk no one would ever believe me cause he’s the nice guy and everyone likes him so I could never say anything! He’s convincing me he didn’t even hit me when I know he did