If you are sure this is due to sleeping in the wrong position, then rest, MOIST heat to the area, and Motrin (as this helps with ibuprofen) If there is no change with doing the above, then she should follow up with her doctor, just to make sure there is nothing else going on.
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Without an exam would have hard to say what it may be. However if she woke up that way, chances are due to sleeping the wrong way. Other causes could be that to anything like meningitis, a viral or bacterial infection. So do try that stuff I listed, but if no improvement in 36-48 hours, then do have her seen.