PP from 2017: you might want to look at the website for Cornell University research program on self-injury and recovery. (Google it.) Lots of great info there.

DBT (Dialectical Behavioral Therapy) is often recommended for teens who self-injure. That approach combines the behavior change aspects of CBT (learning coping skills and alternatives to self-limiting beliefs) with mindfulness practices. It's a heavy commitment for both parents and teens, though, with weekly individual therapy plus weekly "skills training" for both parents and teens. IME, DBT works best when you've got a motivated, mature, cognitively ready kid--not the case with my recovering cutter, unfortunately.

To me, the most important thing is for you to find a therapist with whom your daughter feels comfortable and with whom she is willing to work. And that's probably going to require a lot of legwork and appointments and money to find "the one." (My kid is a therapeutic boarding school right now, so I don't have any recommendations.) If you haven't already done so, you could contact the Ross Center in NW DC; the wheelhouse of that practice is anxiety, and there's usually a waitlist to get an appointment, but someone there would probably be willing to talk with you briefly about your situation and offer some advice.

Here is a good list to get started:

http://www.bethesdapediatrics.com/referrals/psychology

Other practices mentioned here a lot are Rathbone and Associates (especially Julie Baron), Wake Kendall, Ross Center for Anxiety.