Been there, done that.... My worst was way back when I was into making dress shirts for DH. I had a neat pattern that had you fold one side over to make the fron tab and then cut the other side short before folding over to make the facing. Yep, I stitched and cut and ended up with the center front about three inches left of center!
Cut and stitch new ones, toss the "mistakes" in your scrap bag and know that they are fabrics that you liked and will enjoy seeing in a scrap quilt.