Depending on where the damage is, If it is in the seams you can had sew it with a hidden stich. If the material is splitting, depending on where it is on the fabric. If you can not had sew it with the hidden stich, then maybe you can find some material that is colse in color and design. You go to the damaged piece and carefully remove it by hand, relace the damaged piece with the new and hand sew it in place. If the color is to bright You can take those new pieces and I take some water add a couple of drops of bleach, then soak the material in it. Let it lighten to match your old material. Let it dry and then add it to you quilt.