How can I lift my eyebrows that have gotten lower since my teens?

Irregular Trichophytic Forehead lift done at your hairline is what I think will work best for you. See the final incision scar the surgeon does beforehand. More lift on your left and your hairline can be lowered at the same time. 

Yours is a tough case!  You have very deep set eyes and a prominent brow bone.  I have found that when lifting a brow in someone with this sort or anatomy, it is very hard to keep the brow elevated.  You do have enough hair that you could try either an endoscopic or pretrichial lift.But before you do anything, just hold up your brow and forehead with your hands.  When you lift your brow it is going to make your lids look more bony and hollow.  So you would then have to fill in the sulcus. So don't rush into a surgery without having a good idea of how the lids will look post-op!