Cry your eyes out - Idioms by The Free Dictionary
cry your eyes out
cry (one's) eyes out
To cry for an extended period of time. Poor Jane really cried her eyes out during the funeral service. I can't watch those sappy movies because I just cry my eyes out every time.
cry your ˈeyes out cry a lot and for a long time: My son cried his eyes out when we told him we couldn’t afford a new bike. OPPOSITE: laugh your head off