Injection Question
 

I am going to have a filling done on #17 , that's a wisdom tooth I believe , Dentist said it will need a Nerve Block injection but he will do a regular injection first to help numb it , , on July 2nd I had a crown done on the upper molar and I was freeking out about the shot and as it turns out this guy is great , he did 2 injections and I didn't even know it and it was a total blast doing the crown it was actually fun , anyway I asked if this nerve block injection would hurt and he said I will do one shot to numb it first and that's all he said ,,, so my guess is the nerve block injection hurts like hell only from what he is not saying ,, can I have the truth here please , my guess is it kills otherwise he would not do a shot to numb the area first , Thanks