Thanks for the clear pictures. I'd classify them as mostly rolling scars with volume loss, especially on the left cheek area. For this, I think the most effective thing to start with would be possibly multiple subcisions and suctioning. Fillers would also work to restore some of the lost cheek volume. For that you have options that are temporary or permanent. Temporary fillers include Voluma, Restylane. Permanent fillers include Bellafill and a small minority of doctors use liquid silicone, although that is very controversial and always used off-label (meaning that it is not approved for dermal injections, but it can be used that way). Permanent fillers in general are considered controversial, and there are some doctors who think they should never be used, and others who think that they have a place if used only in specific indications like for scars. The risks include granulomas (lumps in the areas injected), rejection of the material, and poor technique which may be difficult to reverse because of it's permanent nature.
This video is of a patient getting injected with Bellafill and he has pretty deep scars with volume loss.
FYI, usually cortisone atrophy does correct itself, but it could take many many months. There was a girl here who started a super long thread detailing her botched cortisone injections. The indentation on her chin area was significant, but I think it ultimately filled in for her. So don't lose hope yet.
I'm not sure what your doctor means by saying you have too much scar tissue for subcision.