There are several synonyms for the phrase "flush with shame." Some possible alternatives include "blush with embarrassment," "turn red with guilt," "crimson with humiliation," "feel mortified," or "feel ashamed to the core." Each of these phrases conveys a sense of deep embarrassment or shame, often in response to a mistake or misdeed. While the exact connotations of these synonyms may vary slightly, they all capture the visceral response that comes with feeling ashamed or embarrassed. Whether you're trying to describe your own feelings or those of a character in a story, these synonyms can help you convey the intense emotions that arise when we do something we regret.