Hello!
If it's just a week after your graft, I don't see a reason to be too concerned about. From what you're describing it sounds like it could be some of the grafting material. You can always go into your dentist and have them take a look too.
Good luck!
Hello!
There could be two reasons the stitch fell out, either you have healed rapidly and it's fallen out on its own or the stitch has come undone. To be on the safe side, I would call your dentist and have them examine the area.
Good luck!