Embarrassment
Shame, Humiliation, Blushing

Embarrassment is a painful but important emotion. It makes us feel bad about our mistakes so we don't repeat them, and one of its side-effects-blushing-signals to others that we recognize our error and are not cold-hearted or oblivious. Shame, a related emotion, can be felt even when no one knows about a slip-up. Guilt tends to focus on what one has done, rather than who one is.