One year my mom made a fire in the fireplace at the house. There was a lot of debris in the fire place and I have no idea how this got left in the fireplace, but there was a spraypaint can in the fireplace with the lid on fire. At the time I was about 9 years old and bending down in front of the fireplace I saw the paint can on fire and said, “Ma, this spraypaint can is on fire!” and she said, “What spraypaint can?” Anyways, long story short, my Dad got a pair of long crab tongs and tried to get it out. He told us to run and as soon as he said that, BOOM. It exploded.
Everything just blew up in the kitchen, including my dad. My mom and I had just gotten out of there before it exploded, but not my dad. He got the brunt of it unfortunately.
Anyways, he had no hair, no eyebrows, no eyelashes, no skin on his face. Luckily there was snow outside, deep snow, in fact we were in the middle of a snowstorm. He ran outside and lay his face in the snow, but that only helped temporarily. So we had to drive him to the hospital in a Jeep. I have to say, I’ve never seen my dad in so much pain, it was really really horrifying to see that as a young boy.
The doctors pretty much told him that a burn is one of the worst injuries you can get. And as far as the answer to the OP, someone pretty much summed it up above when they said that the nerves are injured in a cubed fashion.
It took my Dad a long time to recover, but he eventually did, but not without a lot of morphine and silverdine. Man, I don’t wish a burn on my worst enemy, it’s traumatic. I feel for burn victims.