I forgot to mention that it is very possible you are being too hard on yourself. After the quilt is washed, any small puckering won't show at all...as it will all pucker just a bit. I have to admit also that I use a larger stitch than most folks do....usually a 4.0. I think my machine's stitches are just a bit smaller than they are supposed to be, and the 4.0 is very pleasing to me. (The quilt police should not be around if you do that....)
In hindsight, I am not even sure I would take out all of that last stitch you did. Look at it with fresh eyes today. It might not be as bad as you think. You might have taken enough out to make it work.
Dina