I had so much adrenaline coursing through my body from a survival situation that I couldn't feel any pain until the next day. Only then did I realize how many scrapes and cuts I had all over my legs and arm, and it started hurting.
When your body goes into survival mode, it takes a while to come down off that adrenaline. It wouldn't be unusual for someone to refuse transport to the hospital by ambulance from the scene, and to seek medical attention in the subsequent days.
Actually the first officer to respond had the medics take care of Zimmerman before he was hauled off. He stated in his report that Z had a broken nose, a head injury and his back was wet and covered with grass. It has all been documented but the MSM is still trying to stir the pot.