don't stress too much. =] if your nerve was exposed, it would hurt amazingly bad, so it definitely is not.
your wisdom teeth could be coming in... if there's plenty of space there, you won't need them to be pulled. just call your dentist and ask, they'll probably give you some good advice and you can make an appointment when you can.
I just got x-rays, and I have no wisdom teeth! r00lz!