This one time I had a horrible sunburn as a child and my mom put some vinegar on my back because it was an old school remedy she used. The itch was unbelievable. It was all permeating, I went into the shower and tried to wash it off but it just kept itching, I was crying because of how intense it was, rubbing my bare sunburned back against the wall. Eventually it stopped.
I couldn't verbalize it then, but I probably would have killed myself if it had kept going.