However at three weeks, you have much more healing to do. I can see in the photos that you are improving. However, this process can literally take months. A wise oculoplastic surgeon once said that "ptosis surgery is hell." Even though this persistent swelling is probably not at all what you expected, I recommend being patient. I would not even enter into a discussion of revising this upper eyelid until you are out 4 months for this surgery.
Because the eyelid skin is the thinnest in the body, small amounts of swelling can persist for months. I recommend that patients wait at least 3 months before considering any further treatment. Once all the swelling is gone (in some patients this can take up to 6 months), sometimes non surgical treatments can be used to improve the results (ie skin tightening with Thermi smooth). For now it looks like you are healing well but feel free to speak with your doctor about any concerns.
Some patients will be still swollen for several weeks sometimes longer up to a few months. It isn't clear if your ptosis repair was done by an internal (inside eyelid) approach, but I have seen some patients be droopy just like your's is and then it begins to lift up between a month to 3 months. This is quite rare, however, to see that much improvement between 1-3 months. I would contact your surgeon to go over things in person. I counsel patients that ptosis repairs have about a 10% reoperation rate in my hands as they sometimes can be over or under-corrected. Since your situation was a congenital issue I would give your need for a second surgery a higher probability as congenital ptosis eyelids are never normal anatomically even if we can make them surgically much better functioning and appearing. I wish you the best.
Swelling is a normal adjunct to any operation. The swelling of your eyelid makes it impossible to judge what the final outcome will be.
You are definitely getting better in each photo, with decreased swelling and the lid coming up. Repair of congenital ptosis can be pretty tricky. This amount of swelling is not unusual for a lid surgery. You are more aware of it since you only had one side done. Give it time - the lid will probably come up more, and you may get a great result.