Get her a large mirrow

 

and some drawing instrument (pencils, paper, and clip board, etc..)  Have her draw a picture of herself.  Do it when she has some free time.  During each sitting, draw a complete picture.  No need for perfection, and hopefully, each one is better (more detailed) than the one before.

Have her focus on the eyes.  See if she can make them look at the observer.

You sit next to her and have her draw you as well.

Not a professional advice, just a hunch, to have her be more aware of the sensation of her self.

(Your own anxiety about the problem will only make it worse.  Do not tell her she has a problem.  You yourself should be her first friend.)