Also, even with the same person Novocaine can react differently sometimes (I've had enough cavities to know). And if you have an infection, that counteracts the

Also, even with the same person Novocaine can react differently sometimes (I've had enough cavities to know). And if you have an infection, that counteracts the Novocaine so they have to give you more (had that one happen to me too). Medicine is complicated, yo.