No, under no circumstances should you ever hit her. You can get arrested for that. Why is she scratching you and making you bloody in your lips? Does she have problems communicating that she can not express with words? Beware of someone whose communications skills degrade to physical violence. It may be time to walk away. If she is abusive toward you physically, she is probably abusive toward you verbally. You deserve better from life. Better to walk away now than to waste another year or more on her before you finally come to your senses and then walk away. Sorry I do not have better advice for you, but I still wish you the best of luck. Hit the reset button now...
Ivery