Please please help me?? Facebook and social problem!! Please!?

[Cara]

I'm only a young girl, and quite a while ago, my brother photo shopped a picture of me(edited) and made me look like I have a really flat chest, it was photo shopped too make it look like it was my bare chest, (completely topless) and I then saved it too my phone.
My bestfriend knows my facebook password and was viewing my synced photos from my phone, that had been synced into Facebook. The photo was there, she then showed my ex boyfriend and now he has showed one of his friends. I am scared the photo will be circulated around Facebook, and everyone will be told, considering me and my ex have just split up, we argue a lot and he will do anything too get back at me? Help me?? Please???