Rape, abuse, shame are the major reasons why girls turn to drugs, cutting, Depression ...
It could be some kind of continuous abuse ... multiple rape ... single isolated rape case is rarely the only cause.
Why is she not talking with you?
Shame, self blame, insecurity ... are the main reasons why people don't want to talk about being raped.
Maybe cause she blames you in some way?
Maybe she was raped by someone you know?
Someone you could have protected her from?
Statistically, most child rapes occurs in the immediate family.
It can be father, step-father, grand-father, uncle, family friend, brother, cousin, ....
These are statistics. I am not saying that is what happened to her.
It is your job, as a mother, to find out who it was ... if ...how .. become a detective!
The same person who raped her .. could have reaped other members of your family!