I agree with MarthaT that you might just use a needle and thread to pull the areas together and knot securely. I just finished repairing an afghan that one of my late sisters made for a niece years ago. She did not knot the last row of the afghan and nearly every block had a hole in it. I could not math the yarn weight, so I used 6 strands of embroidery thread and pulled the raveled edges together and knotted them securely. One side looks good and the other shows where I pulled it together. She will be able to display it at any rate.