Where to inject Botox to lift the brows?

Remember that Botox will relax whatever muscle it is injected into. All muscles have an opposing muscle. So if you want an area to go up, inject the muscle that pulls the area down. In your particular question, I would recommend injecting the Botox into the muscle just under the eyebrow, all the way to the inner corner. This must be done judiciously or you may get a temporary droop of the upper eyelid. Make sure that you are going to see Board-certified providers with a lot of experience in this area for best results. 
*Opinions stated here are only opinions. They are not based on a clinical exam, which is recommended. 

The FDA approved 11 line treatment with FDA approved crows feet treatment can weaken the brow depressors enough in some patients produce a brow lift effect.  That does not always happen because the botulinum toxin used to make the 11 line treatment can drift upward to weaken the central brow resulting in weakness and central brow droops.  That is the cause of the Mephisto or vulcan forehead: compensatory lateral brow recruitment. Not so good. Most cosmetic botulinum toxin forehead treatments do not just use the FDA approved areas but also include treatment across the forehead.  This also weakens the muscles of the forehead and produces that stone cold frozen forehead that most everyone wants to avoid.  Study my patented Microdroplet Lift.  It is treatment technique that precisely injects botulinum toxin is very tiny droplets along the eyebrow, crows feet and 11 line area.  The dose applied is typically 33 or 50 units of Botox or Xeomin.  Dysport is dosed differently than these.  By precisely delivering this treatment and leaving the forehead untreated, the muscles at the eyebrow that function to pull the brow down are selectively weakened.  This reduces the work that the forehead needs to do.  The treatment directly softens the resting brow pinch, the forehead lines diminish because this muscle does not need to work as hard against the brow depressing muscles.  There is a mild elevation of the brow, improvement of the brow pinch including the 11 lines, smoothing of the forehead with no brow freeze.

This is difficult to answer without pictures. Usually injections are made to the glabella to lift the brow. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer