If you have a tooth infection and that tooth infection has spread or is spreading you'll usually have a fever and swelling of the gums or swelling of the jaw.
The pain from the tooth infection will also sometimes get worse and won't go away so if you think your tooth infection has spread you should get to the dentist or to the emergency room or urgent care.
Some tooth infections can become severe enough to cause more severe health problems such as heart attacks and possible death.
When a tooth infection has spread you may also have trouble swallowing or breathing or your face or cheeks may be swelling and if so you need to see a dentist, the emergency room or urgent care.
Most tooth aches and tooth infections should go away within a few days if they're not too severe but if not then a dentist or emergency room visit is highly recommended because tooth infections can become very serious.