Withdrawing your application for K1 is irrelevant now. I would not suggest it.
I hope in your personal letter, you did not call in a "criminal absolution".
I am assuming you have a conditional discharge. This means you plead guilty to something. It is no different that a regular conviction, other than HOW it is removed.
Some clients make the mistake (usually because the lawyer is trying to brag what a great job they did) of telling the US that "this isn't a big deal" or saying they were NOT convicted. In fact, you get a discharge of ANY type because you plead guilty. You have to be careful about the wording.