If they're only an acquaintance then I try to reason that their opinion doesn't really matter, they probably didn't give it a second thought and forgot about it and they hopefully reasoned that they're not aware of the full picture or know me well enough to form a strong valid opinion. If they are the kind of person to hold it against me then I am glad that they are only an acquaintance. It sounds a bit aggressive and defensive of me but it's the only way I cope. Those who know the bigger picture and stick by me still, they are true friends which I am very thankful to have. Even though they may be few, I still have more true friends than some people. I still find it excruciatingly embarrassing but this is how I cope.
I suppose that even those who pull away when I have an episode of illness, maybe it's not because they are judging me or anything like that, they may just feel unsure as how to react. They're not walking away with a terrible impression of me, they may just be walking away thinking that they like me but are not sure how to understand me, or whatever.
At the very worst, I try to just pop it into a casual conversation, let them know I'm aware that I can seem different and it's because I am ill. I had to do that with a coworker who seemed to develop a problem with me when I went through a bad patch. She even told the office manager she thought I had a problem with her and that was one reason I had frequent absences. The office manager told me which freaked me out, I had my own worries (ie crashing into despair and barely being able to function). She made it all very much about herself and how my behavior upset her. Fair enough, she didn't understand, not her fault (I am ranting now, but trying to keep my job and life was more of a concern than petty opinions...). So I talked to her. I just said that I am struggling due to recurrent illness and I hope I haven't been rude. She seemed okay after that but we never became good friends, shame. I f she went to the office manager to complain that I upset her again then she'd seem like a complete cow, picking on the sick, so I suppose it is a bit awkward for others... oh well. I have completely rambled. Sorry

I must stress I never did anything terrible to that girl, I just sat at a desk and existed.
Well make of this what you will. I have no idea of my point. I'm just enjoying typing now... Toodle pip.