no, i'm not.  i'm still using others' textures.  hence my ignoring mask solutions for now.  they're a great concept except for what i can see in your image (the ridge around the mouth isn't handled as well), and the really key aspect of matching the makeup of the texture you're using.  it's easy if i, for instance, don't care about having different bump and specularity maps and want to just handle the lips independently.  problem is, the lips will then all look the same but with different material properties.  it will make portraits real boring real fast.  if i made all my own textures, everything would match up, and it would be perfect.  i don't.  and i do want to take advantage of the wonderful make-up and bump/displacement work in the sets i purchase.  so i personally haven't explored masking yet, though i've used it in a simple version on my own and keep reading about them.  P node masks are very cool because they're world dependent.  you can do some incredible effects that way.   

that said, i have plans for two characters for an image that will need some interesting (fantasy) masks.  eventually, i'd like to do my own face painting and special effects, and eventually my own textures.  as such, i'm  very interested in how one would go about setting up the mask with PR3 and VSS.