Try to use a seperate specular map on any parts. Human skin has zones reflecting light different. This is also the case for bumpmaps (inner arm, outer arm, for example). Ask a makeup-artist working in a photo studio to get an idea on which parts powder is a must ;)

With AO, the bottom part is nearly perfect.

By the way: Make sure no intersection occurs. In reality the tissue on the legs will be compressed/deformed, building a deep, sharp fold (with dark shadow). You can't get the same effect without deforming the mesh or fixing this parts via postwork.

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