My guys Storm, I've had him since he was 6 weeks old (we bought him and his mom together) and he has had a few injuries. There are 3, yes 3, that stand out the most.
1st) Storm was about 6mths old, he was boarded at an old cattle barn with pipe stalls with kick boards attached for safety. The end stall had a bit that came out from the wall, a round piece a tube went through and then the door to the stall with another round piece a tube went through. The round pieces lined up so you put the tube through to keep the door shut. Anyway, this particular stall had a little bit wider opening then the others, not so big that a full grown horse could do anything but just big enough that Storm was able to get his head stuck between the bit that came from the wall and the door. He must have reared up in the stall, got his head in the opening and then wasn't able to touch the ground with his front feet. I was out on a ride and there where other boarders in the barn. They went up to the house, and called 911. The fire department came, along with some police. We ended up riding back from the trails to see 2 fire trucks and 2 police cars (we where hoping for a car accident, but it wasn't to be). It turned out that the fire department decided, in their wisdom, to try and cut the bars around my horse with a saws all or a rotary saw or something like that. Anyway, the saw bounced off the bar and promptly cut open my horses front leg just under his knee. Suffice to say Storm then reared up and was able to get free. They called the vet but by the time I got there, blood was spurting (they cut a minor artery) from his leg, we put wonder dust on it to stop the bleeding. The vet came, checked him out and he was fine but the spot where he was cut will not grow hair back.
2nd) Again Storm. We got Storm gelded but it was a little early in the season and still a little cold out. He ended up getting over clotted so the vet had to come out to re-open the incision and pull out all of the clots. He was out with his herd and his play buddy (who the two of them used to play fight, rear at each other, etc.) wanted to play with him but Storm wasn't moving very well. Anyway the other horse ran him into the hay feeder and Storm gouged out a huge chunk of flesh out of his back leg in the muscly/fatty part of his leg. That one was nasty because we couldn't wrap it.
3rd) It's Storm's first show day, he's on the trailer by himself (which he was fine with) and we where on the way to pick up another horse. We went through an area with horse and buggys and one went by the trailer. He had a little freak out, reared up, flipped his head up (thank good otherwise he would have hit his pole) and poked a hole in his forehead where his star would be. He ripped his head open from the hole up to his forelock. We didn't find this out until we got to the other barn and went to open the trailer and saw that his hay net was down. I then took him off to discover the blood dripping down his head and that you could, literally, open his skin up to reveal the muscle underneath. Anyway, we had to put him BACK on the trailer and take him home to his barn so the vet could see him. He went on like a champ and was given 14 stitches to close up his head.
Out of all of these things, none of them scared except the one on his front leg, but that one only doesn't really grow hair.
The joys of horses lol