I've had this happen to me, and it's the worst feeling. Unfortunately there is not a way to retreive a deleted message once it's been deleted.
Follow us on Twitter @VZWSupport
If my response answered your question please click the "Correct Answer" button under my response. This ensures others can benefit from our conversation. Thanks in advance for your help with this!!
If that text was backed up before to iCloud or iTunes then you can restore from that back up. Example. The text was from 2:30 today ... You did a back up to iCloud at 4:30pm.. You deleted the message at 5pm... You can reset your phone and restore your phone to the time of the last back up at 5... It's complicated but depends on if it's worth it to you... iCloud back ups can be checked through settings then iCloud then back up and check time and date of last back up. Hopefully this helps .. It's a long shot tho