I do usually put a couple of stitches in the corners so they lay flat and are "sealed". As to your question on correcting the back edges, I would just use an invisible hand stitch to tack down the excess edges and leave the machine stitches in for the strength of the binding. I guess I am a messy cook because I have to wash my pot holders a lot and would worry the binding might come loose if you picked out the machine stitches. I view pot holders as a utility piece and little imperfections like that just do not bother me!