put your foot in it idiom
UK (US put your foot in your mouth)无意中说出让人尴尬（或生气）的话
to say something by accident that embarrasses or upsets someone
I really put my foot in my mouth – I asked her if Jane was her mother, but she said Jane is her sister. 我真的让自己无地自容：我问她简是不是她母亲，但是她说简是她姐姐。