The operation you had four years ago was just an operation to cure trichiasis! If you have trichiasis of the upper eyelid, double eyelid surgery should be able to improve it. I think it's better to bury the thread and open the double eyelids, because if you are not satisfied, you can return to a single eyelid.
I'm not an expert. I'm just giving you some advice because I'm worried, too. . . I wish you beauty. .