First call your dentist. Explain your symptoms and ask to be seen as soon as possible. Then ease the pain. Take an over-the-counter pain medicine that works for you, but do not put the pills on your sore tooth. Hold an ice pack against your face at the spot of the sore tooth.
Do not put a heating pad, a hot water bottle, or any other source of heat on your jaw. Heat will make things worse instead of better.