I hope this helps
The first item to think about is what caused this damage to the cory and how can that be eliminated.
Second, I do not know if barbels grow back but I would keep the tank extra clean to minimize the numbers of infectious agents such as bacteria and fungus. Also keep in mind corys are sensitive to many medications, so I really would not go that route unless absolutely needed.
A side note, I have many corys who were born with deformed limbs and they do fine, they are going on 6 years of age.
Another thought....I see you have gravel from the photo, a corys substrate should be sand as they forage for food shifting through the sand for yummy goodness, that is the purpose of their barbels...shifting.