I feel for you jib, but I think as you know you were in the wrong. When it comes to work... sucks a dick to say but you have to put up with BS and be "professional". Being that you tried to make a complaint might help you if it becomes a legal situation- but that has a lot to do with how upper management handles it. They could act as though no previous action was taken and then you wouldn't be in that great of a spot....
I've been in situations pretty close to yours tho Jib and when someone catches you on the wrong day a the wrong moment and then responds badly about it- it's pretty fucking hard not to react badly about it all as well. IME, the employer will usually fire both of the people involved, regardless of who started it and who was in the right/wrong. Chest to chest with the bosses best friend... some hung over shit head all up in my face... I try to keep in mind the reason why I am at work tho. money.
Last place I worked was all temps- even the project manager($80k+/yr salary...) and damn near ANYTIME there was an injury, conflict, or problem more than likely someone or all parties involved were going to get fired. Shitty part of capitalism is that money is near God, and if you ain't got a lot of it then you're going to have to take what comes your way...
Best of luck tho Jib- my best advice is to try to get in touch with this guy on a personal, apart and away from work. Try to reason with him, maybe to do something to make up for splitting his face open and you both can keep your jobs. IME even hard-asses will be reasonable if you appraoch them right.
Trying not to blaze ATM... need to find myself a different job ASAP.
Heyyyyyy I didn't say I was right, just that I felt justified. Huuuuuuge difference in my book.

I've had thoughts of tearing this mother fucker apart all day. I thought the beer'd help that subside a bit.... If it turns legal, it turns legal. At this point it's he-said-she-said with injuries on both sides, with evidence of me trying to find an alternate solution. At the very least (in a worst-case scenario), we're both losing our jobs, and an assault charge at this point is just another drop in the (mostly drug-related) bucket for me.
Also, my workplace is heavily unionized. Workplace violence is not tolerated, but it has to be seen by management or vouched for by witnesses to be a terminable offense (from how I've seen it played out before.)
Mother fuckin' Teamsters, brutha-- they know how to look out for dues-paying members.