Okay So I've Done This Once Before And Yes It Did Leave A Scar And Turn'd Brown After Awhile But I just Did It Over The Same One Again Like The Same Scar I Need to know what's ganna happen has anyone else did this same thing should I be really worry'd it's killing me...

You arm will fall off.
Seriously who gives themselves Frost Bite on purpose more than once!!

You didn't learn from the first time... sounds like you're a slow learner.

You should be worried. Tell your parents what a stupid thing you did so they can get you checked out.

You did it on top of the scar, I take it. You want to know what's different about the scar tissue.
Not much. Tougher, but just as many pain nerves. You might get scarring on top of scarring.
Maybe next year you can do it a third time and write a book or go on some reality show.