Hehe, it sounds strange, but this is actually intended
The setnpcskin command works like this:setnpcskin [gender (male/female)][haircut (id)][beard (id)][haircolor (rgb)][eyecolor (rgb)][skincolor (rgb)], for example setnpcskin female 2 -1 0xAA0000 0x11AAFF 0xCCCCCC.
You just set a very dark skin color (black), and since there are no limitations (you could even give her blue or red skin color), you get this resultHowever, the parameters are optional, so if you only want to change the gender, for example, you can simply type setnpcskin female
ah that makes sense. though then its a bug that when i enter simply "setnpcskin female (or male)" that it sets back to a "normal" skin colour? Or will it reset every time i do this? So when i just want to change i.e. the gender i have to enter all values again