There’s an unsend button for messages but not for the look on someone’s face after you said it.

Retrieving the message does not retrieve the moment. Someone read it, something moved in their face, and that happened in a world with no undo, whatever the app later does with the text. The tools have made words feel reversible, and their effect never was. That gap is worth remembering before you press send rather than after.

Treat the sending as the permanent part, because it is. Hold anything sharp for ten minutes and see whether it survives the wait. If you do hurt someone, go and repair it in person rather than deleting the evidence.