Biospira is the name of a product that adds beneficial bacteria to an uncycled aquarium. It must be bought cold and must have been always kept cold straight from the factory where it was produced. Once it warms up, it dies.
You're not treating the fish's wound with bacteria, but adding bacteria helps the aquarium grow the invisible beasts necessary to digest the fish's ammonia output and with the ammonia gone the sore can heal.
Doing water changes works just as well, but will take a lot longer.