Can you screenshot a snap without being noticed? (Mobile phone, Snapchat)

Hey, so unfortunately I sent a very embarrassing snap that was meant for my best friend to a classmate and switched off my internet directly so that it would not be sent. Now it says ‘Send Failed’ can I somehow delete the snap?

It would be really important to me.

Please, if someone knows if it works if I delete the chat or block the guy, it would be very nice if he / she / it tells me.

Turning the cell phone on and off does not work.

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