You can’t recover fully deleted or “unsent” messages, but you might retrieve them through these methods: check if the conversation was archived (these stay hidden, not deleted); download your Facebook data (includes messages up to the last sync); ask the other person to forward or screenshot the chat; or — on Android — dig into the app’s cache (com.facebook.orca/fb_temp) to restore local data Third-party tools claim to help, but results aren’t guaranteed and may risk privacy.