Despite two injections of anesthetic, Amy Anderson felt like her dentist was jamming rods into her tooth during a root canal. She writhed in pain as her infected tooth was hollowed with a drill, its nerve amputated, and then sealed.
I am not a red-head and I had to have FOUR injections before I became numb enough to have the root canal done. It has nothing to do with the hair color, IMO. And generally, I withstand pain very well.