prick (one's) conscience
To cause one niggling feelings of guilt or remorse. It pricked my conscience to see my brother being led away in handcuffs, but I know it was the right thing to call the cops on him. Their promotional material is carefully crafted to prick the conscience of anyone who picks it up.
prick your ˈconscience
, your ˈconscience pricks you
make you feel guilty about something; feel guilty about something: Her conscience pricked her as she lied to her sister.