Most of the time no one acted like anything happened at all. I've never had a professor say anything. I would often blush after raising my hand and asking a question or saying something just because I realized I'd said something (which of course makes no rational sense)--but professors usually love it when someone asks any sort of decent questions because it helps them feel like they aren't just throwing words at people who don't care or aren't paying attention.
Outside of class situations, on a couple of occasions I've had a person quietly tell me afterwards 'no one cares that X', with X being whatever stupid reason I was blushing for.
I've also been in situations where some people thought it was the funniest thing in the world that I blushed, so they did anything they could think of to try to make me blush.
mg: I'm so glad I'm not in school anymore.
