It seems to me that you have two options:
1) Stay and feel the need to CYA on a daily basis about everything -- this is NO way to live
2) Seek employment elsewhere
Ages ago I worked in a place where I actually kept a personal log of everything I did and every interaction I had. Obviously I didn't use patient names but date/time/rm number. Also, put on it my interactions with family visitors etc etc. I "won" if that is what you would like to call it. However, that woman's opinion of me dogged me for about 4 years. Sure she slandered me after she left but suing someone? Life is too short and being someone that brings lawsuits doesn't exactly make you an attractive employment candidate -- even if you are "right" and win.
I'd be interested to see what you patient care manager comes up with -- but most managers are rubbish at sorting these things out with a win-win. But if she can do it YAY for her.
You can, of course, try discussing it with the RN in question, but you would need to approach in quite a benign manner. Given that it has been escalated to the patient care manager already that really isn't an option.