Did you ever read any of the goddamn Harry Potter books? You basically get the flu once a month for the rest of your life and for three nights a week, you get to be in terrible agony as your body contorts and twists you into a werewolf. Then you have no idea what you do as a wolf, and if they lock you up, you end up gnawing yourself into nasty wounds that never heal because they're magic in nature.
If you're talking Buffyverse werewolves, mostly the same deal. And there, it takes a scratch no matter what time of the month it is.