Not on par with many of the stories above, but...

I was eight. Mum had made a stew in a pressure cooker, now switched off for some time. I wanted to try some, but knew that I had to wait for the pressure cooker to cool before unlocking the screw lid. In order to ascertain the cooker's temperature therefore, I tested it. With my lips. Only to find myself stuck to the hot cooker lid by my lower lip.

Lost quite a bit of skin and had to be fed through a straw for a week.