I have the same issue. I have had some red marks last years. I am trying the v beam to get rid of them.
I've had what I thought was hyper pigmentation for years after cystic acne. Turns out most of them are flat scars that somewhat resemble hyper pigmentation, but under bad lighting are ever so slightly "pitted". It's scar tissue, which can be flat (or almost flat) and a slightly different color than the rest of the skin. Mine are a weird gray-ish purple tone that looks dull and unhealthy. Cystic acne damages the skin and even if you aren't with true pitted scarring, you're almost always left with dull skin/scar tissue. Remember that after any injury, your skin is NEVER as healthy as it was before.
Stayed the same unfortunately. I use skin plumping topicals now to help make them less noticeable and it makes a huge difference. I can send you a picture, I also have one in my gallery but it's only one side of my face and not sure you can tell what I'm talking about it. Most of my flat scars are around my mouth, but look like hyper pigmentation in pictures.