Girl lied and said I hit her but I didn't what should I do?

[Future234]

My ex girlfriend and I recently broke up and we hadn't really talked for about a week. Then we ran into each other in a bar and hooked up but then got in a big argument, she pushed my face out of the way and I pushed her beer out of her hand thats it. I was with my friends and she was with hers and my friends saw the WHOLE thing. The next day she's telling people that I hit her in the face and gave my number to some dude who texted me threatening me. I never hit her and never even came close to it because im not like that also my friends witnessed it know she's lying as well. Why the H*** would she make something up like that I could get in real trouble. She was texting me the next day trying to convince me that I did and she said "you were blacked out how would you even remember" but I wasn't blacked out. Later I told her that I had had enough and was going to contact the police because she gave my number and I was being threatened and and harassed on social media. AS SOON AS I MENTIONED POLICE she freaked out and said "its not necessary to take it that far, its all over just let it go" now correct me if im wrong but if a girl got hit why would she freak about the police if she was telling the truth. She was lying she knows it I know it, but she's spreading rumors so should I go to the police or what?
P.S - I really don't understand why she would make up such a serious lie such as this one that has serious consequences. She called me a week later wanting to get back together and I was like wtf NO. If she cared why would she try to destroy me.