An idiom about regret: Don't ... (3)
I believe the answer is:
cry
(Other definitions for cry that I've seen before include "Shed tears" , "Blubber" , "Sound of pain or grief" , "Call" , "Don't . . . over spilt milk" .)
I believe the answer is:
cry
(Other definitions for cry that I've seen before include "Shed tears" , "Blubber" , "Sound of pain or grief" , "Call" , "Don't . . . over spilt milk" .)