Texture for scultured character head

i tried to make a character head out of cube by sculpt tools but it needs very much subdivisions for details(at least for me noob) it goes well but problem comes when texturing the head it is impossible to unwrap thousand of faces my quick wrap is also bad (it didnot load edited snapshot or applying it) may be i have done something wrong but is there another way to texture high face mesh lessening face count make head bad
please help me thx in advance

try this video. the technique most people use in blender is to bake the sculpt to a normal map and using it in place of the high poly sculpt.