Wonder how your light setting was. Dunno as well due to no sample shown how bad the problem is. 

To see how occlusion master works by the examples in this thread.

1.) lips: You can see how the shadows are between the lips.
2.) Ears: Will try to explain here as much as I can on this one. This is the first place I look at so see how well occlusion master did its job. You can see the shadow applied from the lighting around the earloobs.

3.) Eyes: Although I do not see much of a difference here. Hard to see, it is their. 

Lighting does do a crucial role in Occlusion Master. It does help, even on neck area, and around other parts of the body.