I want to begin by flipping the image horizontally.



Make a new layer (ctrl+alt+n) and set it's mode to Overlay (overall Opacity +50 %), brush ? Soft (brush Flow = 5%-6%).

Paint all over the face picking colors from the image itself.

Here is where I have started: Further and further ? changing the skin tone like we want.



Change eye color. Use Brush modes and color:







Result:



Now I want you to create a new Top layer with Normal blending mode. When it is done, just paint with Normal Brush, set Flow about 5%-10 %.

Render the skin, beginning: