i would make 4 new .5 squares and put them properly together, turn under a .25 seam allowance, then blindstitch them over the dog's mouth, er, over the ruined 4 patches, with a teeny, invisible slipstitch, by hand. on the back do the same with a piece of backing, just make a patch, maybe with a frame around it, or make an applique with one of the front colors. in between, i'd carefully pat in batting to match the rest in fullness. you might want to glue the new fabric down with school glue while you work to keep things from shifting. then machine stitch over it all. even a profession will have to patch it. if you stay with the dark to dark and light to light you won't see it unless you know it's there. it's good that it's busy.