Blow up in (one's) face informal verb phrase common
To abruptly explode or blow up.
The bomb blew up in her face in a crowded street.
The artillery shell blew up in people's face and injured several people.
Used to say that a plan goes wrong or awry.
I regret to inform that all our plans blew up in our face.
My plan blew up in my face mainly due to a lack of finance.
It was often said by a photographer when he would like small children to look at the camera and smile before he took a photo.
When the photographer said “watch the birdie”, all of us looked at the camera and smiled.