Is it possible for a deviated septum to go away on its own?

A septum is a hard structure separating the left side of the nose from the right side.  Expecting a septum to fix itself is like expecting to come home one day and finding out that your bedroom wall has moved 2 feet to the left.  So, all jokes aside, the answer is no.

A deviated septum will not straighten on its own, but your breathing may be improved with the use of a nasal steroid (such as Nasonex or Flonase) under the direction of your physician.  While this will not straighten the swelling, it can reduce some of the swelling or inflammation inside your nose - which may improve your breathing.    

If your injury was a few months ago, the septum by now is probably where it will stay.  It does not bend well. 

Thank you for your question.  I am sorry but in my experience a deviated nasal septum has never corrected itself.  The fact that you have nasal obstruction means that she will most likely need a septoplasty.  Please consult and experienced board certified plastic surgeon.