I am having severe pain on the left side of my mouth. The pain starts in my lower molar (second tooth from back), and then spreads to the tooth above it, and then will continue to spread throughout the rest of my teeth and gums on the left side of my mouth and up my jaw to my temple. Both molars where the pain starts have previously had cavities, and the lower tooth has a crown. The pain is excruciating, and the only way I have been able to stop it is to keep cold water or tea in my mouth, once the liquid starts to reach body temperature the pain will start again. I am taking 4 advil at a time now and it does absolutely nothing. I went into my dentist today and she took an x-ray and said she did not see anything wrong with the teeth. This has been going on for three days now and only seems to be getting worse, what should I do?