This happened to me on my first quilt that I was hand quilting. I was able to fix the seam. Wasn't 100% but it is on black and not that noticable unless you really look. I like the fusible web idea. And, on another quilt I was making for my boss....I tried things I'd never done before, basically designing as I went and machine quilting for the first time and it looked good and she loved it but to me......it almost went into the fire!!!! So, even if you can see your mistakes, others can't. I'm sure she will love and cherish the quilt.