it's been 3 days since surgery and my eye is still droopy. When should I expect it to be fully correct? (Photo)

Its still too early to be able to comment on the result. Things are swollen and it will continue to improve over the next couple of weeks. You should have a good impression of the result after 6 weeks but it depends on what type of ptosis repair you had. It can take months to fully settle. See your PS for reassurance.

Just a few day is so very early from a surgery like this.  You need time to heal.  Much more time.  I would say you need 4 to 6 months to know how this is likely to heal.

Did they do an internal or external repair?  Sometimes the post-op swelling will weigh down the lid so that it won't open fully.  So give it a couple more days and see how you do.  If the lid stays low and they did an external repair, it can be adjusted early on.  If it was from the inside of the lid, you will have to wait before doing any revision.