The material has its map in the center of the map. DAZ has it as a part of the head layer. It is a bear to texture there if you use the head layer.
I use a separate map and just have continuous skin there on the head texture. Using a dark Poser color probably does well enough. But because of the overlap, if you use the head layer, either you get skin on NOSTRILS or you get too dark a texture on the skin around the nares. ( there is demo in a thread below- yesterday or the day before- that shows the effect of being too generous with the Nostrils colors on the head layer.

material Nostrils

Until Bloodsong decided to make the bottlecaps inside the nares a new material in P4 so that it was not just skin and thus get rid of it, there was a glow in the renders.
DAZ incorporated this same refinement in Victoria and Michael from the outset.