I'm glad you're re-working this skin. One thing I'd point out is that all your weathering is just plain old black. If it's worn that heavily and that thickly, it would be the camo pattern underneath, rather than simple shadows. Run up a fast camo layer, stick it under your white layer, and turn your black smudges layer into a mask, or an alpha, that actually shows through to the colors underneath. See how that looks.
Just a thought.