I have repaired a couple of vintage quilts, and this is very common. I put some "Heat'n Bond" Iron on adhesive seam sealer or "Seal a Seam" under it, and tuck the seam allowance under, and then whip stitch it. With the "seal a seam" in there it holds very well. Good luck!
Yikes! Is the backing already on? If not, I would try to remove this block and re-stitch. I'm a beginner, too, so I can commiserate. Best of luck to you, quilting chum. Let me know what does work.
I'm not a quilter, but I agree with Sewonforever.
Hi Pam I like Sewonforever's suggestion. Sounds like a good fix!!PS Sorry i did not get back to you about Tues. where are the kits? When I have a vehicle would like to swing by to see and purchase them. Also, you are inspiring me to put a quilt on my plate to do. Love yours. WOuld like to see the pattern.
I had this happen several times with client quilts. And twice with one of my own,LOL all after they were partly quilted on the LA. I took a square of matching fabric and slipped it under the seam & slip stitched it then quilted over it for stability. It will never be noticed especially with a scrap or busy quilt.