I made some rotting skin shaders quite some time ago. One version is available in my Free Stuff (Icky Skin Shader)

Examples in THIS THREAD

FREEBIES! | My Gallery | My Store | My FB | Tumblr |
You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.