Should I file a police report?

Recently I was just assaulted at a gas station. I met up with some people there to talk about some drama that went on. Well, turns out they bring about 20 people. And one of the guys wanted to fight. I told them I wouldnt fight just wanted to talk, so he slapped me in the face. His older brother, whose 18, kept urging me to fight that guy. Well I didnt, so he said he'd fight me if i didnt. I continually told them i wasnt going to fight. I tried walking to my car but they pulled me away from it. Next thing I know I get punched in the face and kneed in the face numerous times. Got a split lip and some scratches and a fat lip, but other than that. I'm fine. Does that merit an assault charge? An officer came to the scene just as I was leaving but it didnt stop becasue I was shocked. Also, I know if this person goes to jail, people will be after me. Please let me know what to do!