Ouch that sounds very painful for both her and you. Im not really sure what to do either but i can relate to this kind of thing so i thought id respond. When the youngest here was around that age these kind of things happened sometimes. It usually would work itself out in a week or two. Teens can be frighteningly cruel to each other, i remember one time where the youngests best friend turned into her arch nemisis and back again inside of 24 hours(which confused me as i was still hating the "friend", kids can forgive easier i guess). I am at a loss as to what the answer is or how you can make things better for her but listening to her and letting her cry seems like the only thing you can do. Man o man am i glad im not a teenager anymore. Its amazing any of us make it thru such a stressful time filled with so much cruelty and back stabbing.