Bert,
First to your specific situation; it is exactly because you are such a caring and compassionate Doc that this hurts you - if you were an @sshat, you would have already forgotten her.
It's one thing to go out of your way to help someone, and have them not appreciate it, adding insult to injury is when they turn around and kick you in the crotch. That is just mean and a demonstration of poor character.
the reality is that people's true nature shows through in moments of stress and duress. Be glad she is gone to be-devil some other soul.
In a broader context, you bring up social media, and tracking what people are saying about you and your practice - there are some fairly straightforward things that folks can do to keep tabs on such things.
One of the easiest is to setup Google Alerts so that you get an email whenever your name or your practice name is mentioned on the Internet.
The second is to nicely encourage positive comments/posts via a sign/note/flyer posted somewhere in your lobby area suggesting that patient feedback is welcome, and some examples from other patients.
There is much more to the subject, but that is a start.
Again Bert, Water off a duck's back, seriously.
