Thanks for all the comments guy’s, much appreciated.
Subedei, my process is pretty basic, I use a mixture of hard and soft brushes of different sizes in photoshop. With the hard brush I block out areas of colour and with a soft brush with a slight opacity of about 60% I blend and shade areas of colours. All the veins etc.. were done with this method. The texture on the skin I uses a texture brush on a separate layer covering the area I wanted the effect on, and changed the layer opacity and blending options until it blended the way I wanted it to.
heres a GIF demonstrating the steps of creations from dodgey sketch to finished piece, hope this helps:
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