Here is a statement from the actor about the incident:
“I literally shot that scene for a day and a half and I had to dance like an idiot in the suspenders. At one point, the clip, which was a crocodile clip, got stuck in the television as I’m crawling towards her and she’s right in front of me and she’s laughing hysterically. I had to ping it, and it would go past my face. And this time I’m crawling towards the bed. It gets stuck. It releases, flies over my head, hits her in the head, slashes her head. I cut her open. Imagine a studio, and in three seconds, everybody’s gone, and I’m just sitting there in my boxer shorts and my boots and a pair of socks and I just started crying. I just scarred Hilary Swank!’ I almost took her eye out and I just made a fool of myself for two days and this is what I have to show for it. She’s off to the hospital.”
Swank recovered and has since forgiven him for the incident.