I saw a photo long ago of a girl who was forced to sit on a red hot barbecue, in Uganda, part of Idi Amins period of debauchery and torture. Not a pretty sight.
I had a 3rd degree burn on my shoulder from concentrated sunburn on a dull day. I was in jeans and long sleeves but a patch on my neck got blasted I was given a cooling & healing burn gel plus special burn dressings. It hurt a lot but was easy to treat and healed well.
The back of my neck got bad sunburn when I was a kid on a school camp. I got blisters and it stung like hell.