I think it depends very much on what you're trying to accomplish - it could be to hide/minimize the appearance of a scar or blemish, or any feature that distracts from the final image you've envisioned. If the makeup has the end result of making the model appear like
- he/she just walked off the set of Miami Vice, Season Three
- a $30 hooker
- a cosmetics counter demonstration dummy
then it's probably NOT a fine art nude. Unless that's the look you're going for, to make a point about models in makeup.