I can only think of 3 things.
1. In edit mode select each edges and make sure that the edge crease is 0 on each edge. Also make sure that mean vertex crease is also 0.
2. Normals: 2 different methods.
A) Go to properties editor->Mesh data tab->Geometry data panel->If the button says Clear custom split normal instead of Add custom split normal. Note: If you did any custom normals work it will remove it all.
B) Select the edges and press alt+n->Reset vectors. Note: sometimes this doesn’t work. The workaround that usually forces it to work is with the offending edges selected press Alt+L, then press M and move mouse around shading will go crazy since all the selected split normals will point towards the mouse. Then left click to confirm. then do the alt+n->Reset vectors.
3. In edit mode press P->Loose parts. Tab to object mode, select the head, and press H to hide. Then check to see if there is any other objects that shouldn’t be there.
***Edit***
Thought of a 4th, but not sure if that would give this problem, but just incase. Goto wire frame or x-ray mode and click select->select by trait->select inside faces. If anything gets selected. x->only faces. You may have to go thru and clean up edges afterward too.
