Expectations of Brow Lift to Reduce Frown Lines?

Thank you for your question. Shaping the brows is one my favorite parts of using Botox. It requires a very detailed understanding of the underlying anatomy as well as assessing each individual while they are animating their brows. By carefully placing Botox in the muscles that depress the brow, you can cause the brow to rest and relax in a lifted position. There are limits to how much you can lift, and for some surgery is better option. Incorrect assessment or placement can also lead to the reverse effect, so overall technique is critical. You can also shape the brow different. For example, you can raise the tail of the brow vs creating a raised arched brow vs creating a raised horizontal brow. It depends on the individual's desired brow aesthetic goals. I would consider this a very advanced technique so I would query your injector on their experience in this area.
As far as how many units may be needed, this also depends on which part of the brow you want to correct. For the inner brows, you may consider ~20 units (same as the frown line treatment). For the middle or outer brow, I generally use up to 5 units on each side.
You may also want to consider adding fillers to shape and raise the brow. Combining the two products can work synergistically together. As far as surgery goes, it is a better procedure to address any skin laxity that may accumulate in the forehead, upper lid, or address severe brow ptosis.  A physical exam would help determine whether a surgical solution is better for you.  I would recommend that you visit a board certified plastic surgeon who can help guide you with your options.

If the frown lines are your primary concern you can get a nice result with botulinum toxins.  If your brow position also needs to be corrected then I would recommend a brow lift with, corrugator (frown muscle) resection and fat/fascia grafting to prevent reattachment of the muscle.

It is important to understand what causes wrinkles in the forehead in order to determine if a brow lift will help. Forehead wrinkles, like others in the upper face, are related to muscle hyperactivity, which is why they respond to Botox or Dysport. However, the reason the muscles are hyperactive is often because they are working to hold up a sagging brow. In that instance, Botox will make the wrinkles go away but the brow drops. A brow lift will hold up the brow, allowing the muscles to relax, in turn allowing the wrinkles to soften. An experienced plastic surgeon will be able to evaluate and advise as to the best option.