First, there are no rules.
Rules are for sports and other forms of civil conduct. Assault is most definitely uncivil.
Your goal -- should you realize that is this one of the rare instances where you need to physically fight back -- should be to disable your attacker long enough to escape. Strikes or gouges to the eyes, throat, groin, and knees are most quickly and effectively debilitating. These targets are not pain-dependent, are easy to find, and you don't need perfect aim or great speed and strength.
Sometimes this is referred to as "dirty" fighting. I simply call it self-defense. Personally, I feel that calling self-defense somehow "dirty" bathes it in a transgressive mystique, simultaneously fascinating and transgressive. I don't buy into that usage. Self-defense should not be relegated to the fringe of indecency. (I prefer to reserve the phrase "dirty" fighting for instances of sports fighting where one contender uses illegal techniques to win.)
We are the only species on the planet that not only largely discourages females from learning physical safety skills, we also largely and deliberately disseminate MIS-information about women's abilities to fight effectively. The 411 on women's self-defense is emPOWERing.
Learn more about self defense classes in Seattle -- skills you can use.