I once slid down a steep hill with old pavement and took roughly a full square foot of hide off. My left thigh had a 10" by 4" oval abraded off. The left calf was a bit smaller. Left forearm was missing a 5" by 2" oval. Etcetera, etcetera ...
I got home at about 2100 and called my girlfriend, an RN, to tell her not to come over after her shift was over at 2300. She told me to leave the front door unlocked and to get myself into the tub to soak the gravel out.
At about 2320 she showed up, got naked, climbed into the tub with me, and, straddling me, she proceeded to use a plastic comb and nail brush to lovingly scrub and comb the sand and gravel out of my hide. The scrubbing was done with plain soap and warm water. Rinsing as the dirt and blood obscured the action. The last pass was with Betadine. Once cleaned she dried me off, slathered on a layer of Neosporin, bandaged the rough spots with gauze, and put me to bed.
She came back every twenty-four hours to redo the bandages. If any of the raw areas get weepy or the borders are red and swollen it means your fighting an infection. Go back, scrub well with soap and water bebriding the area and follow with a strong scrub with Betadine. Apply more Neosporin and rebandage.
Key there is, once you have the wounds cleaned out, to keep the scabs that form moist and flexible by keeping them covered with Neosporin. After the scabs are covering the wound completely you can substitute Vaseline. OTC pain medications, Tylenol or Ibuprofen help moderate the pain and Benedryl helps with the itch. If during a bandage change the gauze sticks simply soak the area until it loosens up. Use more Neosporin or Vaseline when you rebandage to prevent it happening again.
You can spend a lot to get special gel bandages and various creams, potions and pills but plain gauze pads, roll gauze, Neosporin and Vaseline, and OTC medications work.
A week or ten days later the worse is over and you can look forward to your next round of road rash.