It kind of depends. Are your facebook account clean enough that your employer could see it? Clean enough for your grandma? Clean enough for your kids?
..and even if all this is true, medical professionals aren't allowed to say hi to you on the street because that might tip of others who see it that you are a patient of theirs, and that is confidential. If you say hi first, however, they are allowed to say hi back. I don't know how it is where you live, or with NPs, but where I live, an NP would never accept a friend request from a patient, so there wouldn't be much point in sending one.
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AQ: 42/50 || SQ: 32/80 || IQ(RPM): 138 || IRI-empathytest(PT/EC/FS/PD): 10(-7)/16(-3)/19(+3)/19(+10) || Alexithymia: 148/185 || Aspie-quiz: AS 133/200, NT 56/200