Looks like you have a few issues there.

Firstly, I don't think the Fastscatter node is that great for skin - it's more suited to waxy objects.  Also, looks like you have AO switched on for the main light - I suggest using the AO nodes in the material room rather than light based AO (light based AO doesn't give great results on faces, since the nose and other features cause too much shadowing).  If your whole scene is lit by an IBL light, you wont getting any specular - so you need to use some normal lights too to give your render some depth.

Photo realism starts with using great texturemaps and bump maps.  Then you need perfect shadows, a realistic face shape, and skin materials that handle light in a similar way to real skin.  On a portrait, if you don't get the eyes right, your render won't be convincing.

Check the tutorials in my sig below - will explain how to do some of those things.

Creator of PoserPhysics
Creator of OctaneRender for Poser
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