Farrah Abrahamis claiming self-defense after a female security guard sued her over alleged injuries she said she suffered at the hands of the reality personality. The Teen Mom star filed a response to the lawsuit obtained by RadarOnline.com, in which she claimed that if Megan Yakita Armstrong was injured in the alleged incident at a Los Angeles bar, then it was due to her own negligence and no fault of Abraham. We broke the story — Armstrong sued the ex-MTV star in January, claiming Abraham “struck” the side of her face. She claimed she was forced to seek medical attention over the alleged inj…