remove hard shadow-advice

I have a 40 year old snapshot of a woman. It is scanned from an old "silk paper" print.

It has a number of other problems. I don't want to undertake to improve ii if I can do nothing about the hard black shadow. I've tried and failed. Liquify leaves me with a dark outline as in a child's coloring book.

Any suggestions?

Image may be NSFW.
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thanks,

vince