I know it disinfects the wound, but what about that makes it hurt so much? And why doesn’t it hurt when you get it on non-injured skin?
Alcohol kills living cells by dehydrating them. Therefore, if you put alcohol on a cut, you’re killing cells (the bacteria that you intend to kill, but also your own cells) and that hurts.
Just to be a bit more specific, you are dehydrating nerve cells and that hurts. Most of your cells have no way to complain about being mistreated.
Don’t anybody tell the tree-hugging eco-freaks… 