I know i did the wrong thin but what should i do?

My friends and I were down at the park. One of my friends had brought his slingshot and we shot a small rock up in the air. I was a one in a billion shot and it hit a kid practicing baseball in the head. His coach came over and asked us about it but we denied it. He seemed slightly hurt but he could walk. My other friend who was there but not involved might tell his parents what happened, and if so I will be in a ton of trouble. I know i did the wrong thing, but what should I do?