Glowing armpits! At least it's not the nostrils, eh? :D

I can only speculate that maybe it looks like a break in the model or something. Maybe try zooming in to that area and shooting off another render to see how it looks?

 

Currently using Poser Pro 2012 (Display Units = feet)

AMD Phenom II 3.2ghz (6 cores)

8gb RAM

Windows 10 Pro 64bit