I think the execution of the flesh tones is fantastic! Great job in mixing the various tones. What exactly is it you are not happy with?
The beard stubble does look feint, but as you say it could be a photo issue. You can try some black weathering powder. Just a little dabble is enough, and the stipple method with a brush also adds the look of texture.
For the eyes, you could add a light wash of red, and let the flow accumulate at the inside corners.
regards,
Jack