Great question. It is difficult to say without seeing photos of what concerns you. If you have two droopy eyebrows with one being more severe than the other, yes a browlift will help. If your eyebrows are in good position but one functions better than the other, potentially Botox to treat the more active side is the best option. Seek a consult with a facial plastic surgeon to fully discuss your options.
We are all uneven. All faces are assymetric and are not made of wood. The brows, especially, are very dynamic structures that constantly change position with different expressions. So, it is impossible to make the brows exactly even with a brow lift. While it may be possible to lessen extreme assymetries, the best results retain the natural normal dynamic assymetry of the face.
No. Botox is a great way to even uneven facial musculature.