Appreciate your skepticism, for FreeRepublic often suffers from chronic group think. Feel sad Trayvon's parents had to bury their child, and equally sad Mr. Zimmerman had to make a deadly force decision.
I'm mostly angered by media attention whores whipping up angry mobs reminiscent of a Klan lynch mob atmosphere. Worse are the race baiting politicians pimping the tragedy for fun and profit.
You've made a good point here: The police video tape shows no dressings on the back of Zimmerman's head
Wound appears as surface abrasion (road rash) but the lack of dressing atop the wound surprised me a bit. No sutures without a transport is logical. Head wound without a dressing an ice pack, later swelling is likely.
Freeper JoeProBono contributed this photo image. Known as a joker, I wouldn't rule a photoshop image. Asked for a confirmation of authenticity, but I haven't heard back. 
Cheers,
OLA