Yikes. That sounds ugly.
I was at the AMA festival of speed at Road America in Elkhart Lake wisconsin on a Vesrah Motorsports built GSXR-1000 AMA superbike. Practice day before the race weekend. Needed new tires but was going to change them over lunch, figured I had a few more laps in the rear.
Well I got mixed up with another guy, it got real, and before you know it we're both heads down dicing it up. I passed him in the carousel on the inside (it's a LONG, very fast right hander), flipped him the bird under the bridge, flipped it left in to the chicane. Flipped it right, and the rear tire decided it's had enough. I'd overheated it so bad in the carousel passing him that it was just thin goo and had no grip left. So it stepped out on me.
Launched me like a catapult. Suddenly I'm flying through the air, things get real quiet for a few seconds. I flew over 50 feet through the air. Plenty of time to think about how bad it's gonna hurt when I hit pavement again.
Well, the pavement came. I landed on my left forearm first, bounced, rolled a few times, came to a stop. Looked up just in time to see the guy I'd passed in the chicane bearing down on me. He'd frigging target fixated on the mess on the pavement - my bike and I were both center track. He took the lesser of two evils and ran me over. Human instinct is a bitch.
Well right before the impact I tucked my head down. He impacted the rear of my helmet and top of the neck at ~85mph, all 500 pounds of bike and rider. Hardest I've ever been hit by anything in my life - it pinballed me off the track about 60 or 70 feet. Huge impact. Found out later it cracked my helmet in 3 places, destroyed the aerodynamic hump on the back of my leathers, and for weeks I had horizontal bruises on my back from the alpinestars back protector I was wearing under my suit.
The gear saved my life.
I tried standing up after I stopped, realized my leg wasn't working and fell back down. (I found out later at the trauma center I had severed ligaments in my ankle, and a broken fibula).
Tried to prop myself up with my arms and one felt on fire; pulled my glove out and a wrist bone was jutting out.
"Well, that explains that."
But the worst damage wasn't visible. The guy who hit me broke every safety rule on the track and pulled off. He parked his bike against the armco and came running over to me. Somehow the corner worker had missed the crash. No flag came out.
He yelled at me and said "are you ok?"
I said something unintelligible to him, but sounded perfectly fine to me.
I don't remember much after that. I don't remember anything for about 9 months, in fact. Anterograde amnesia, couldn't form new memories. I was functional. I could work. But I would end up doing the same job twice, or three times.. Wasn't hard, I mean, I couldn't remember screwing things up from day to day. Summer turned to fall, fall turned to winter.
I had word salad bad, the whole time. I got words mixed up all the time, couldn't get out what I wanted to say. It was.. rough. After the amnesia finally started to fade, and the brain healed up, I struggled with that for a couple of years. Still do, time to time. Certain words elude me. I had to find new ways to link things together in my head.
The body healed (mostly, ankle tendons that were severed were inoperable). But the long term effects are still there. Hurts every morning, in various joints. Get bad headaches sometime. The impact changed my neck geometry enough that I started developing circulation problems in the vertebral arteries. Had to go through physical therapy to get that resolved; the headaches I got were so bad I actually, truthfully, quite literally wanted to die.
But I persevered. Got through it all. Got healthy again, and do what I can within my limits. Th more active I stay, the better everything works; joints stay flexible, osteoarthritis meds help some with all the cartilage damage, and the brain works well again.
It was a rough go, for a while. though. Gave me a new perspective on how important the little things are. How each moment is precious.