How long does it take for swelling to go down after an upper eyelid lift?

Looks good in a week. But it takes a full year for surgical incisions anywhere on the body to heal completely.
Not very long. Usually swelling is gone by 5-7 days. Eyelids heal very rapidly.
1 - 2 + weeks. Generally most of the swelling subsides in 1 - 2 weeks but in some patients it may last longer.
Quick. The majority of the swelling will go away within the first 48 hours if you keep your head elevated at all times and keep cool gel on the eyes. There may be some small amount of swelling that persists for a few weeks. Usually this swelling is only noticeable to you and your doctor.