There is a saying: "A Prophet has no honour in their own land". In translation, it is sometimes easier to hear and act on suggestions from those that are not related to us. It's challenging these days to see the beauty in ourselves when the media keeps negating who we are and trying to make us believe something else! Maybe finding someone that the girl looks up to is the answer. That person can then share some of their own experiences and gentle guide/show the girl a more positive view of herself. I'll share a story:
I once met a teenage girl via some friends. Gracie was beautiful, very exotic. But in her teenage mind, she saw herself as too tall, too fat, too ugly. I sensed this immediately upon meeting her. So, I told her if you ever want to model let me know. Several years later, she called me. We met and she said she wanted to model I said okay. What are you willing to do for this goal? She said whatever I need to. Are you ready to give up your fear? Yes and she really meant YES! Long story short and months later, she won each pageant she entered, became a contestant for Miss America and placed! She lives the rest of her dreams happily.
Moral of the story, she really found/saw herself which was separate from what anyone else thought or imprinted on her.