The phrase implies a failed result, often unexpectedly and with negative consequences. The surprise party blew up in his face when the guest of honor arrived early.
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Emotional Impact
The phrase can express frustration or dismay due to plans going wrong. Her elaborate proposal blew up in her face, leaving her devastated.
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Consequences
It's often used when there are significant consequences to the failure. His dishonesty about his credentials finally blew up in his face during the interview.