There is a tricky magenta and yellow quite hard to get rid off properly without affecting magenta and yellow we want to keep, so it's a trade-off... like if a part of the picture gets old faster than some other parts (you can see it with the chin quite clearly if you play with curves, as the chin gets in the yellow way faster than the remaining face, and vice-versa.
First I get rid of the paper texture was the easiest part -> G'MIC > FFT(fourier transform) -> paint black on the surrounding stars (don't touch the big one in the middle!!), then FFT again to reconstruct the picture.
2nd, take a sample of the cast colors in the eyes or the tooth -> new layer Divide, you got a pretty idea of what the white balance should be (play with opacity)
New from visible, isolate the BG to blur it slightly then curves, saturation tool, playing around -> new from visible - change blending mode to my liking... a lot of trial and new from visible
In the end I'm thinking that you might have taken the best path by painting over