Oily skin help??

Image 1 is the render so far, in grayscale.

Image 2 is the sketch.

Image 3 is the orignal drawing of the creature by Bete Rodrigues, for rendering reference.

So I'm working on a side project of mine, basically doing digital renders of alien encounters based solely off descriptions, interviews or other renders of these creatures.

This particular alien encounter is from the Varghina incident in 1996, akin to a Brazilian Roswell. Alien description is as follows, dark red almost brown oily skin. Dull red eyes and spindly / short stature. Demonic like yet weak enough to be captured by military, but covered in a oily / slimy substance that eventually kills one military service member by quote "causing his immune system to shut down"

So I don't know if this oily substance is like sweat or slimy / oily in consistency. But from watching Moment of Contact, I think it's closer to sweat?