I would just quilt it the way it is. At this point, there's probably not much you could do except unsewing and re-sewing. I was going to recommend starching, but you've already done that. This kind of quilt can actually become a family favorite, especially with children, because it's the quilt that's okay to use to make play tents with, cuddle with when you're really sick, use for picnics on the floor or outside in the back yard, etc.
Sometimes you just have to finish up a UFO and move on......