The defense has evidence that Zimmerman had injuries and received treatment for them the next day. According to the reports I saw, the evidence of his injuries was from a medical report and that medical report was dated the day AFTER the attack.
First of all, it was a good day for the defense, I will concede that. However, an injury does not mean you are innocent of shooting an unarmed teen dead using the defense of self defense.
You cannot be the aggressor, get the worst of the fight and shoot someone, stab someone or kill someone and claim self defense.
Let's look at it this way. I am walking down the street minding my own business and a man attacks me and tries to sexually assault me. I just happen to have a black belt in karate and I start kicking his ass. I give him a black eye, I break his nose. He can't then shoot me dead and when arrested say it was self defense. Well, he can but legally if it can be proven he attacked me first, that is not a valid case of self defense if he is the one who attacked first, if he was the aggressor.
Second, while its interesting that Zimmerman's defense has evidence of his injuries, this was for treatment the next day. How do we know he did not go home and do that to himself or got into another fight. I would like to see photographs, evidence from the responding officers or paramedics of that they saw on him a few moments after he killed Martin.
The prosecution can raise reasonable doubt if those injuries were only treated for and documented the next day.
Also, unless I missed it, I did not see any evidence comparing any injuries on Martin to that of Zimmerman.
So at this point the fact he had injuries, its relevant yes but does not prove he is innocent and killed someone in self defense.