Quote - Then Paint over it; keepng in mind that white areas will cause bump and Black areas will do nothing.

This is actually wrong. The correct info is that neutral grey (50%) is the 'do nothing' part. And Blacks < 50% dip while whites > 50% bump (you can flip this by entering -ve numbers in the bump sliders of the material). Which is why you get the issue that Ghostofmacbeth is talking about. A simple image invert will make wrinkles, which are dark into light shades and they will bump up when you want them to dip down.

So doing separate selection ranges for the various parts and painting some of it by hand is pretty much the only way to get accurate bumps. A simple invert will fall apart at any kind of medium/close up of shot the skin. Levels also will affect the whole skin in undesirable ways if you don't do proper selections first.