Remove the torn pieces and replace them. It is just tedious but can be done. You can mark the seam allowances on the replacement fabric so you have the stopping points. Starch the pieces and/or use freezer paper. It's one seam at a time. You can do this!
Trim off the hex edges and remove any frayed edges even if you lose a little of the design. Stay stitch around the whole quilt. Press again and then add straight borders.
It's a beautiful quilt and certainly deserves your time and attention to compete it.
Your side kick is a cutie!