I am a tattooist and I am subjected to these kinda things. (Though it is always best to talk to the person who actually performed the piercing)
The tounge is a muscle and if you puncture a muscle and let it heal, the hole will shrink if nothing is kept in it.
It was a wound. Just because you have a stinging sensation does not mean the hole is still there. Just as with any other scar, you will always be aware of its presence.
Chances are, you will need to have it repierced.
As far as the nerves and infections go, that all depends on WHO is doing it and WHO is taking care of it. You do have to treat a tounge piercing different than any other because of the fact it is in your mouth (food, bacteria, etc.) but as long as you do use good oral hygeine practice, the chance of infection is actually pretty small.
Tips on cleaning. Always use mouthwash (the blue kind is the most effective) AFTER the piercing has healed, be sure to brush your tongue along with your teeth (top and bottom) make sure you have cleaned the beads on the bar thoroughly. After you have done this a couple of times it will become habit.
I have had my tongue piercing for going on 7 years and have never had a problem with it.
Just make sure you keep going with a thorough mouth cleansing process every day.