It's hard to see what is going on without knowing your settings ... but I'll offer this as a possible solution. Combine the head's bump map and your head displacement map into one image. And then use IT as the displacement map. 1) Put the character's head bump map in Layer 1. 2) Put your displacement head map on Layer 2. 3) Set the displacement map to "Screen" blending mode. The result will be the bump map and head map merged together. 4) Save that out as a JPG image, with little to no compression, and use that as your displacement map. This pic might help.