In most states not, because the incident/injury for which you went to the hospital was outside your normal duties at work and you were not hurt in the performance of those duties, but honestly, in New Jersey, I'd probably consider filing a worker's comp action. They're fairly liberal with the employee in most cases. They may tell you "no" and deny it, but it might make things look better for you. Your co-worker, on the other hand, had no injuries, no trip to the hospital, and that's just one thing that might make you look much more believable. Since it's distinctly a "he said/he said" with no witnesses and no way to prove what happened deal, they may not do anything to either one of you.
Are you continuing to work together? Have you returned to work? Where is your employer in this whole situation?