I fixed it... sorta. It's still not the best and you should (and better) update it and edit it largely. I just gave you an idea and a base to work with. You kept on doing things like this:
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Exhibit A: Circles Red and Orange show where you left white marks. Why?
The yellow shows the pinkie, or what is that? Look at your fist, does your pinkie wrap around under your ring finger and partially your middle finger? I would hope not...
Green notices the thumb. It seems almost completely bony aka jacked up.
The blue recognizes the whole top part of his fist as empty, as in it's wrong. Your fingers aren't little stubs, that is one of the main problems of your original.
There are stray marks across the canvas, and the shading on the fist was messed up too. I don't think my shading is the best for it either, but try harder! This looked almost perfect before and I'm sure you are about to nail it.
* Open in paint to see it better.