I think you did a great job.
As for the shading on facial features, with acrylics I find it works best doing a flesh color overall, then do a wash that is a mix of a reddish brown ink and an olive color paint (less olive if you want a paler complexion), then go back with the original base color and pick out the highlights, doing a few highlight layers on progressively smaller areas adding a bit more white/lighter flesh color to each
Then I often go back again with an even more thinned wash sometimes to tone things down and get rid of the contrast. Kind of an iterative process
I also use glazing medium to thin the wash or highlights and make it more transparent. Water surface tension is not ideal, but adding something like a drop of dish soap, or the glazing medium will help it lay down better and less prone to the rings as it dries. Also the glazing medium will extend working time a bit allowing you to blend better
You can also do stubble facial hair effects by using some glaze medium with a dark black/brown or black/blue color thinned almost to wash consistency
