Today I had an instance when I was fixing a letter and got a little worried if during the tikun I may have done lo kesidran . Its one of those things that keep nagging at you even after you are done. I'll admit it happens to me every now and then.
It was a nun that was quite far from the letter on the right. So I added ink to the back of the nun to make it closer. First the gag, then coming down to the moshav. When reaching the moshav I made the bottom right thicker with a series of thin strokes to the back of the moshav. I did the strokes in quick succession, sort of sketching it. Its very possible that after one of my strokes I had created a tzurah of a gimmel. But before I had a chance to fully comprehend the situation, I had already continued with the successive strokes and filled in the gap, and was left with a fully kosher nun.
So the question is, since I do not have access to slow motion replay, only a bad feeling that maybe there was a shinuy tzurah for about a half a second, what is the status of the parsha now?