I tried making a texture maps to make a crackly look on nose of model and even bumpy look to insides of mouth much like the Guts tutorial on blendercookie. However, even though the lil ball for showin how it will turn out looks perfect, when I render my models the bumps or cracky looks never apear.
There are tons of reasons why the bump map texture will not show up. Perhaps you can supply a blend file showing the problem? Chances are that you use the wrong mapping method or the material layers are mixed/stacked the wrong way.