question: Hello, I had 2 root canals done in the past month in a half. First was Upper back left tooth and then the one second next to it. My left side of my face and temple were pounding as well as the tooth, along with pressure...this was after my second tooth.. dentist opened it back up and let it breath, then retreated. All was well for 2 weeks. Now face pain and throbbing are back but now it is the tooth with first root canal that feels pressure and throbs. Could this be another failed root canal and could this be why the side of my face is throbbing? I also have not been feeling well since this all started..such as lathargic and mild sore throat ...as well as metalic taste that seems to only be on left side of my tongue . Thank you. Paula