Damage to the chorda tympani component of the lingual nerve can lead to altered taste. Like other nerve injuries, this usually does improve over the course of a few weeks. Some of these injuries are longer lasting, and some are permanent. Odds are that it is temporary and will recover.

Not a bad idea to stop injections in the same region for a period of time to avoid irritating the injury while it is in the healing phase.

Hope that helps.

Ross