How long does it take for nerves to grow back to normal?

Burning is not the norm after nasal surgery. Itchiness, numbness and tingling can last up to 12 months post rhinoplasty which usually occurs on the tip. Your symptom could be helped with steroid injection. Hope this helps. 

It can take nerves 12 months (or longer) to completely heal following this procedure. Many patients will have normal sensation by 3 months, some take 6 months, and others 9-12 months. If it was an open rhinoplasty then it may take them longer, especially since you had a septoplasty (more dissection). If you didn't have the burning sensation initially and then it started it could be due to several things: Neuroma (the nerves are healing but some got stuck in scar tissue or can't "find their way" so create a sensitive area that may go away), webbing of the incisions creating a raw spot on the inside of your nose not related to nerve repair at all (try vaseline or antibiotic ointment to the area if you can easily reach it), issues with the septum healing from the septoplasty, or dry rhinitis from the improved airflow drying your nose out (try saline nasal spray for a week or 2 and see if it helps the discomfort). Since 2 doctors looked and didn't see any problems with incisions or the septum I would continue to wait it out, but in the meantime try saline nasal spray or antibiotic ointment if you can reach the area for at least 2 weeks to see if that helps.