Can I retrieve deleted messages?

There is nowhere to retrieve them from, since they are not saved anywhere but on your device(s) that reeceived them. Text messages, once delivered, are purged from the message handling servers (and if undeliverable after just a few days, they are also purged).

If you have an iCloud or iTunes backup made before you deleted them, you can restore that to get them back. A restore from backup will also replace the entire device contents with the backup contents and state.