Attached Link: http://www.stewreo.de/poser/firefaq.html#7

For a quick fix, see FAQ #7 on my web site. *"can anyone say why the nostrils are glowing in the first place?"* Yep - they're a consequence of how shadow maps work: First, shadow maps are usually blurred to simulate soft shadows. That can cause that small details in it get lost - like nostrils. Second, shadow maps are slightly offset to avoid self-shadowing. This means that shadows are a tiny bit "detached" from the surface that is actually casting the shadow. To fix cause #1, the first thing do to is to adjust the area covered by the shadow map - the : If you're using spotlights, keep the cone angle as narrow as possible in your scene. For directional lights, zoom in the shadow lite cam so that it covers only the things that actually need to cast shadows (e.g. in a portrait, legs don't need to cast shadows). Last thing to try is increasing the shadow map size - this is really the last thing to try, because in contrast to the others, it significantly increases the render time and the amount of RAM used when rendering. For #2, you can often decrease the shadow bias of Poser's lights. The default is playing it safe, so you barely ever get self-shadowing in Poser. Quite often, you can safely lower the bias without any unwanted side effects. Or, the quick and simple way out: Use raytraced shadows or AO.