Bringing in more highlights, using the textured brush below. The side light is added on a separate layer. Fixed her nose somewhat and brightened her eyes.

Blending and refining the highlights. When I smudged the highlights, which were on a separate layer, the texture kinda got lost so I used the eraser with the same tip lightly over it to bring back the texture.

I figured since she has white hair, she would have white eyelashes too. I played with some white strands in the eyebrows too, but the results made her look really scary :p so I only kept the white eyelashes.

I used some variant of the Tinting brushes in Painter 8, the ones with grain, and papers from the "Crack Textures". They were used on an Overlay layer on top (but below the side light layer). The particular settings shown above aren't exactly what I used, but the general idea here is, you have to crank the contrast and brightness way up, and vary your paper scale so it doesn't look repetitive.

In this last step here, I also added some subtle blue veins on her forehead/temples, around her eyes, and around her mouth. The blood vessels tend to show up there, at least that's the way it seems on my face.

The Sharpen tool was used on some highlighted areas, again to add some more texture. I changed the colour of the secondary light to a much brighter, light cyan.