How does wiping a scratch help one's skin feel better?

Wiping? With what?

@Jeruba My hand. I lightly scratched my arms, and the pain felt better after I wiped it with my hand.

Ok, you mean a scratch that occurs as a slight accidental injury and not the result of your scratching yourself (as to scratch an itch) with your own fingernails, right?

I don’t know the answer; I’m just curious about the question.

@Jeruba A scratch from my fingernail.