I'm struggling with a restoration/color correction task for an old photo that was framed with a mat:
As you can see, there's a definite difference in the regions that were covered vs. exposed. I've tried making my own mask, using selection transformations to feather/fade the edges to even out the exposure. But I still end up with an obvious "ring" (the matte is oval) that I can't seem to get rid of. How can I remove the obvious oval shape (in Photoshop for preference)?
(For avoidance of doubt: the blurring on the face is not on the original; it is there to protect the privacy of the individual)