Recovering deleted Messenger messages is tough since deleted chats are usually permanent. You can try checking your Archived Chats or Message Requests folders, or download your Facebook data to see past messages. Asking the other person to resend the conversation is also helpful. Be cautious with third-party recovery tools, and if you have phone backups, restoring an older backup might help—but could erase newer data. To avoid loss, archive chats instead of deleting and back up your data regularly.