I fix a lot of worn out quilts for various other quilters, just completed one that was 50 years old and the young man passed away, so was very important that I correct it without disturbing the original design and fabrics. I use lace a lot to make repairs, the lace should match the color you are trying to fix, cream and white are my first choice, just use school glue and paint a light coat on the lace, tuck the pieces together as best as you can, let it dry then use your sewing machine with tiny stitches, do a zig zag perhaps, you may have to place a small piece of fabric or lace on the underside of your background, to help stabilize your work. Sometime I use crayola crayons so you cannot find the mend. If you use the crayons, lay a paper towel on the crayons marks, and hold a warm iron on the spot, to lift off any excess wax.