Here are the progression of the skin.

I painted him in the following stages, 1:1 Tallaran Flesh and shadow grey > Dark flesh glaze on all the recesses, followed by a wash of Devlan Mud > 1:1:1 Tallaran Flesh, shadow grey, skull white > 1:1:2 Tallaran flesh, shadow grey, skull white > Leviathan purple glaze in the recesses and topple it of with pure skull white as a extreme highlight.