
Taylor S. answered 03/26/20
Energetic Medical Student Who Tutors in Science, Math, and Writing
I think there's more than one reason salt hurts so bad on wounds. One reason is physical: if you look on a microscopic level, salt crystals are super rough, so skin that is already injured isn't going to like this new coarse material cutting into it.
Another possibility has a more chemical nature. An excess of salt will produce a hypertonic solution around the exposed cells. In other words, the extra salt outside the cells will draw water out of them, which understandably could be a problem. Also, some studies have suggested pain receptors in our skin get activated by changes in ion concentration, and if this is the case, dumping sodium chloride on those newly exposed receptors would definitely do the trick.
Hope this helps!