Video of Zimmerman entered the police station has been released. I don't see any blood. I don't see any grass stains. I don't see anybody who looks faintly like they were on the loosing end of a fight. The clothes look neat and unripped and he's walking well. I don't see how it coincides with the police report.
All that said, Zimmerman's nose is a bloody (or not) distraction. Zimmerman's condition, though interesting, is irrelevant to the actually issues which matter. Namely that Martin, who was walking home and minding his own business, was shot and killed by a man who remains free. None of those facts, best I know, have ever been disputed.
Here's a link to a Sanford government website that offers some answers to many questions.
Update, April 21: There is some blood. And no, it's not life threatening. It's also still irrelevant. And I can't help but think that perhaps Zimmerman deserved a little ass-whupping for his incorrect pursuit of Martin.