There are many different techniques to repair ptosis. Some surgeons use permanent sutures and others use sutures that are removed or dissolve. So I am not sure what technique your surgeon used. I would recommend asking him/her.
The first thing to be said is that although it is a permanent suture that we use to suture the levator muscle in ptosis repair, it is extremely fine and of narrow caliber. Because this is a muscle that is constantly in use, the repair needs to be strong to avoid dehiscence. The suture we use is inert, meaning it does not cause any tissue inflammation, and, shortly after the repair, it becomes covered with scar, so that it is walled off from the rest of the body. It is not anything for you to worry about.
Thank you for sharing your concerns. There are several surgical techniques to repair ptosis. From your description, the sutures are probably permanent. This is the correct type of suture if you had levator advancement. I hope this helps. Good luck,