Purple scars after salt and ice... 3 days after, what to do??

Show your parents and have them take you to the doctor. You have stupidly given yourself a bad case of frostbite.

And adendum. If you come across something that is a challenge, i.e. Cinammon, salt & ice, etc, don't do them. Chances are it is something that's really dumb and, like the salt and ice challenge, will most likely leave you scared or with medical issues for the rest of your life. Better for the moment of ribbing.

I bet you feel like a real genius right now, don't you? I bet your "friends" (or whoever talked you into doing something this dumb) were having one hell of a laugh at your expense.

At this point, what you have is frostbite, and the damaged skin, if bad enough can get infection. It can leave possible permanent scars. You should have it looked at by a doctor, to be sure, the injury does not cause more serious damage