Daughter cuts herself?

My daughter a single mother to my 2 year old granddaughter obviously needs help. She's the 2nd of 4 and when she hit puberty things started to get difficult. It was rocky, and sometimes scary. I've offered her counseling when she was 14 and than again when she was 16 but she was not really interested and dropped out both times after a few sessions. Today, her boyfriend told me, that she has cut herself Saturday night, after she found out, that he is still in touch with his ex (she lives in Australia and they talk once in a while, but he says its nothing serious), there was a lot of blood, but thank God no deep cuts. She locked herself in the bathroom & refused to come out. She made him promise not to tell me, but he's scared & we both are clueless. I know, she wants attention & I want to give her this attention, but its just never enough. She tells people that I don't love her, but when she is with me, it seems like t's ok. When I try to talk to her, she brushes me off.