Ways to retrive deleted iMessages on iPhone This may be a popular question, but I have not seen a very satisfying answer for it. It is unfortunate when one accidentally deletes iMessages because all of the history of that message is gone, and there appears to be no way to get it back on the device itself. 

Are there existing apps that would recover messages onto the device?
I am not aware of apps that can recover messages from your iPhone. If you accidentally deleted messages off your iPhone, you would need to restore the iPhone from your most recent iCloud or iTunes backup.

The restore will bring back all the SMS/iMessages that were present on your iPhone at the time of the backup itself.