I have a friend who claims her dermatologist told her than sunscreen was what was burning her skin. (I think it's much more likely that her rash/burn was either a sunburn, a skin reaction to some other product, or a "sun poisoning" type rash from using a sunscreen that doesn't block UVA -- my wife gets that.)
Said doctor told her it's because sunscreen converts the light energy to heat, and that heat was burning her skin. I know this is technically the way those organic sunscreen ingredients work, but can anyone quantify how much heat would actually be produced by this process?
Some web sites claim that some users feel hot when they're using absorbent-type sunscreens -- and again I find that hard to believe. Make me want to slather a few hot dogs with different sunscreens (and a control with none) and leave them in the sun and stick them with my meat thermometer to see if there's any discernable difference.