I agree that channel Mixer is probably helpful to bring back some overall reddish tengue to the skin.
However i feel that due to the tone evening the slightest imperfections of the skin do not become visible anymore even though the structure is still there.
For example in the upper part of the arm you can see a red dot. While this is probably something I’d remove, I’d like to preserve the red on the smaller pores and imperfections that make the skin look natural. That is probably what i would call a good skin.
Currently experimenting with a combination of Channel Mixer and a Mask created by desaturating the base layer with Mono Mixer by pushing reds to maximum and greens and blue to a value so that only the pores of the skin remain.
Not convinced yet but probably a solution…
Maybe you should show the whole photo so that it is easier to see the difficulties you are facing. In my opinion, the cut-out of the Photo with the hand is too blurred to be able to see fine details of the skin.
Moreover, the logic of the lighting has been broken by smearing the transition at the hand (this can be seen in the clothing, which shows sharp separation between light and dark), which can also lead to a distorted impression.
Maybe you should just even out the color between these two areas and leave the differences in brightness as they are with a sharp border and coarse details of the skin.
If we rethink this image from capture, using a fill flash equal to your exposure or just under it would eliminate those shadows. Not helpful here, but food for thought for the future.
I did a quick test to get the whole impression and didn’t put much effort into the retouching. I just quickly removed the shadow from the skin without paying much attention to the details.
And I think that if you want to remove the shadows, you have to remove the shadow from the whole skin to get a uniform look:
For me is far more important that her beautiful smile is well expressed. This is the central element where the eye of the beholder should be directed (lighten the skin, enhance the contrast and a subtle vignette).
As for the details of the skin, the biggest work should actually be on the residual layer. There you should try to balance the colors and make as few changes as possible on the scale layers (only the sharp transition to shadows).
What can also be very helpful is to create a transparent layer over residual layer, to use an airbrush tool with very low opacity, take the paint from the residual layer at the appropriate places and on the transparent layer paint over the areas of the skin that need to be improved:
