Your application is an opportunity for you to make the best first impression you can. As a result, it is always a good idea to focus on the positive, rather than the negative. That's why I would recommend starting off with something like "I would like to take this opportunity to highlight the improvement in my performance between ___ and ___. Although I started off with ___, I was able to really improve my score with a lot of hard work and effort. I am confident that I will have even greater success upon admittance to ___ law school." (or something to that effect). That way, you are downplaying the fact that you might have done badly and trying to focus their attention on what you did do well. Good luck!
Alisa Greenstein | Veritas Prep Admissions Consultant | www.VeritasPrep.com/law