I am not sure, If I get you right, but if you apply a decal as overlay over the face texture (upper right side of the texture tab, not upper left), this will be like a mask over the face. Gloss, specular and normal maps don't work well on that overlays. If you have a main face texture and overlays covering the biggest part, I suggest to better combine texture and overlay with a painting tool and use that combination as the main face texture.
If you allready know all of this and only have issues with the normal map: There are many things that can go wrong with creating normal maps. Be sure your normal map works as good as other ones from downloaded looks or the VaM originals (as you know, if you don't add an own normal map, VaM will use the default one from custom/atom/person/textures/basic woman). Sometimes you have very strange effects with a slightly defective normal map.
If this still is not the issue you have with your texture maps, then I can ensure you: Yes, there are still some flaws and issues in VaM with textures. Most of the time they are barely visible, but if you go deep into texturing with combining many maps, you will probably see them. I find it really difficult to name the issue, because it is hard to find and maybe some of it is even only subjective. I suspect the face region to be worse than the body region.
If it is an issue within VaM, there is little or nothing you can do about it. MeshedVR already stated, that he won't fix minor issues with the VaM 1.x version any more, and will put all his manpower into the future new version 2.x
