Minimum Waiting Time for a Second Brow Lift?

Actually this is a common scenario- the lateral brows dropping after an endoscopic browlift, due to the sliding of the skin and brows over the sub-brow fat pat at as soon as several weeks after the procedure. I usually recommend the lateral subcutaneous limited browlift that can be performed under straight local anesthesia, and takes less than 1 hour to perform and heals up quickly in most cases.

1 year - Yes - Yes ... are my answers to your questions.
Being patient before revision surgery always pays off! Although there is no strict rule, you will likely experience a little more settling of the brows over the next 6 months although much less than during the first half a year. Surgically, it is relatively easy to raise the central brow. The temporal brow tail on the other end requires convincing measures for it to stay up after a browlift. Therefore, a browlift is more of a resculpturing procedure than a simple lift.

You would be best off to wait one year before beginning the process of second brow lift. As your question suggests that you understand, there will be more relaxing of the skin and healing to occur.