Glasses. Glasses fix everything! Maybe a wig with long hair you can use to cover the face.
Shoot her face from odd angles. See
this. The "Asian Honey" pics are night and day.
If you need to show her face, shoot it from far away or out of focus. Or extreme closeup. (Lips, eyes, etc) If her teeth are nasty, keep them lips shut!
I realize your budget is limited, but maybe you can get a 2nd actress who may not have a nice body, but has a great face to stand-in and just do facial/reaction shots. She wouldn't have to strip or anything, just make faces at the camera, so it may be cheaper. (Might have to have them both wear the same wig or something so it looks like they're the same person)
If all else fails and you go with the paper bag... let's see some great paper tearing!
