if u advertise massage services and LE comes in and u claim "i'm just doing massage" they will ask for ur permit to do so. without it you are preforming an illegal service.

doctors, cosmetologists and masseuses are people with licenses to TOUCH.

as far as i know bodyrubs and massages are different in the eyes of legality.
the nude part... hm. well in san diego the law is a nude entertainer (who has a permit to be nude) must stay 6 feet away from patrons or be ticketed if caught. so, legally i would guess that its a NO-NO to do nude massages.