dental injury while playing broomball. who's responsible?

In the ice link get-together, we played broomball. Accidently, i hit a guy's face with the broom and as a result his tooth died. He accused me of his injury and asked for a full dental payment. I didn't want to mess things up so i took full responsibility and paid around 1500 dollars as he gave me his dental bill.
As i paid the money, he told me if i just paid the money he won't ask for additional payment later on, which he now says "we can settle additional cost honorable" and saying " It was only a matter of time for my tooth to weaken and turn gray since it is dead and is not getting any nourishment."

The accident happened in Virginia around 2008 september. and i came back to Korea, my homeland, and is currently serving military. And two days ago, he sent an e-mail saying that his tooth got grey and was necessary to have a crown on it, and asked me to pay another 1500 dollars with his dental bill photo. I don't think i'm responsible, at least fully responsible for the second payment. Also, if he sues me there's no way that i can fly back to states cuz i'm in the army.

As he participated in the broomball, he must've realized the possibility of injury, and also he knows it's a sports involving physical contact. Also, i think the responsiblity of being careful also is partly on him too so i don't think i have to pay all the moeny.

If his tooth getting weak was a matter of time, wasn't he supposed to do something else for his tooth?

and why should i be fully responsible for something happened 2years ago?

What should i do? what happens if he sues me?