I don't think I make a face, but then again, only a very chosen few (like 4 people in my entire lifetime) outside of doctors know for a fact I wear diapers, but nobody has ever mentioned anything so I'm assuming not. On the other hand, most
courteous people wouldn't say anything even if they did notice it.
I've caught myself staring off into space or pausing what I'm doing (washing dishes in the sink, for example) while I wet, but no face I don't think. I do occasionally shiver, but it's probably barely noticeable unless someone was really paying attention.
I've known people like your neighbor, though. They make rude remarks or backhanded compliments and then say "I'm just kidding" because they think it's funny. The behavior typically stems from insecurity and trying to fit in ("ha-ha! See, I'm the funny, gregarious one!"). Same goes for the interrupting. So if I were you, I'd look at it from the perspective that
she is the one with the problem.
If she truly is a healthcare "professional" (nurse) and she did notice your diaper, it is VERY UN-professional of her to point it out. Even if nobody else was around.
I honestly doubt she knows - but even if she does - the other neighbors probably just disregarded the comment as "that's just the way she is" (awkward/weird/rude/brusque).
I wouldn't worry too much about it. Even if they all know, who cares? They're not going to say anything (except for maybe the rude one). Most people are so absorbed in their own life, an hour later they had probably all forgotten the incident entirely.
I'm not quick witted, so I never know how to fire back when people make comments like that. But I do have a knack for avoiding people I dislike. And that's what I would do here. Just make a point of not acknowledging her or giving her the opportunity to embarrass you.
Life's too short to be around a-holes.