I've been scalded twice by radiator-water (automotive radiators, that is) in my life.
The first time, I was 16. I had plans that day to wash and wax the family car 'cause I was going to use it. I looked out the window to see if the car was home, then I took a shower, ate, and went outside. Unknown to me, my dad had used it while I was busy, so it was hot. I opened the hood, and thinking it hadn't moved all morning, opened the radiator cap and BOOM. Kind of second-third degree burns from my shoulder all the way down to my hand on my left arm. Part of the skin from the hand up to roughly the elbow sloughed off when I ran to grab the hose and rinse my arm off. It was kind of funny actually to see a two foot long by two inch wide section of skin just fall, plop!, to the ground at my feet. The flesh that had been under it looked bumpy and pinky-white.
Anyway, I ran that hose on my arm for a good two hours or so. That helped a lot with the pain. After the pain was sorta-manageable (that is, barely able to suppress screaming), I just let it breathe.
But!
I had to go to school (high school that is)... so that meant using whatever I could find in the bathroom to cover the wound so the gauze I wrapped around it wouldn't stick to it. My arm was wrapped in gauge for about a month until it felt ok enough to go without it (not continuously - unwrapped it at home for breathing and whatnot).
My skin grew back (I thought there'd have been scarring or something, like that guy in that movie Darkman, but it grew back fine. Hair and everything too. It's a little lighter in shade than the rest of my skin and it tends to sunburn a bit easier too, but otherwise looks normal.
As for the second one, I was lifting up the vent lever on my radiator cap (like a couple years ago) and the radiator cap had a fatal failure and broke. It shot up in the air like about 30 feet high with accompanying geyser of hot water and steam, with my (again) left hand in the middle of it. This one was not as bad as the first (just my hand, and no skin feel off). I ran into the AM/PM and bought a bag of ice and a 64 oz cup, ran outside, dumped ice in it and filled it with water from the service pump and stuck my hand in. I kept my hand in there for about 6 hours, replenishing ice as necessary, and after that it was as if it had never happened, felt fine and great.
As for chemical burns, never had one, but I hear you are also supposed to flush with large volumes of water for about 15 minutes (or you could just jump in the tub with cool water for an hour or two).