Hit a parked car without knowing it and now I'm in trouble, what's going to happen?

The insurance agency called me saying that I have to take my car in to get it inspected. The accident happened April 9th and a cop called me a week after.
Here is what happened: I was going to the gym and when I parked my car, I noticed some scratches on my car. I thought it happened at school and someone ELSE did it not me, so I went home freaked out. APPERENTLY I had hit the girl beside me. I had NO IDEA. I got a call from the cops saying they wanna charge me with a hit and run. However, I explained that I didn't know I did anything because I had no clue, and she said okay and told me to explain my story. I did and she never called back. I hadn't heard anything until now, and it was a liability call from the insurance company saying I have to get my car inspected. It was a message on the answering machine and I'm waiting for my dad to get home (I'm 20 and I'm on his insurance). What's going to happen?
Added (1). Oh, and the scratches on my car were just that. Scratches. I had little paint scratches, while the other girl was a really nice new infiniti that apperently got dented. How my tiny honda didn't get dented and hers did, I have no clue.

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