Boni, I hestitated to comment, because while i do see your effort, there is a lot missing. I see you have made some nice rosy cheekbones. But what i miss most of all, is depth and skin pores. Your specular settings are way too hight for this lightning.  Eyelashes and brows too blurry. I see you painted over a merchant resource. That is a good practice. In my example i used photos on the model( projection mapping) and painted a lot of details on the skin. I tried to get skin as oily as yours.

 

You have to built up the pores. I would take with a colorpicker the darkest color and the lightest. Then i would make a skin color chart for that skin, in other words, i pick different colors between the lightest and darkest color. I paste every color from light to dark next to each other. ( you can do same for make up) If you use photoshop, ( i fetch from my 3d painting program to photoshop.. via a plugin) try to use noise brushes to add some difference in the skin, and some sharpness. What you can do is, alter the scatter brushes( i alter them, so you dont need to download skin brushes) You can also make your own. If you need more help i will try to explain more:)

 Even though the example is still a wip skin, you can see bumps, irregular skin and even some scarring.  I painted a lot on the skin to remove shine on the diffuse map. I didnt get it quite as oily as you but colored skin absorbes light differently. and is most of the time oilier.