Often times they will regrow no problem. That is if it doesn't keep happening back to back. Couple of mine survived our 28°f night yesterday under just 2-3 layers of sheets thrown over them.
Next spring I'm gonna plant one in the ground in a microclimated situation and one without my protection at all and see if they come back after a whole winter without any extra help. I've had other non cold hardy plants come back up here in 8b after winter without protection. Avocado, Jack fruit, longevity spinach, Okinawa Spinach, Brazilian spinach, waterleaf, etc all come back after being froze back the whole winter. Granted it usually only gets into the 20s here but can hit the mid teens every several years.