can you retrieve deleted messages

In general, no. Go to Settings/[your name]/iCloud. Is the switch for Messages turned on? If it is, there is no way to recover a deleted text message.

If it is off and you have a backup that was made before the text message was deleted you can restore that backup to the phone, however, this will replace everything on the phone with the contents of the backup; essentially it will set the phone to the state it was in at the time the backup was made.

Here are the are instructions for restoring a backup→Restore your iOS device from a backup - Apple Support, but note that this will restore your phone to the way it was when the backup was made. Any changes made to the content of your iPhone since then will be lost.