Stubborn hyperpigmentation/tightness years post surgery - what might help? (Photo)

A few years ago I had a mid face lift as well as an endoscopic brow lift. My right side of the face is fine, but my left has been left with stubborn hyperpigmentation. It worsens/gets darker whenever I don’t get enough sleep or take medication that retains water. I can also feel the tightening in that area in those instances. Is there anything that can be done to make it go away? I don’t understand why it’s there in the first place, but it’s been there since the surgery. Thank you.