let emotions show
let (one's) emotions show
To allow one's emotions to be on display to others; to let other people see how one is feeling (about something). He is normally a very composed, reserved fellow, but he'll let his emotions show if ever you say a disparaging remark about his sister. She held it together for the whole funeral, but she they started talking about her childhood with her father, she started to let her emotions show.
let one's emotions show
to be emotional, especially where it is not appropriate. I'm sorry for the outburst. I didn't mean to let my emotions show. Please stop crying. You mustn't let your emotions show.