If you ever notice, any form of swelling, bleeding, pain, discoloration, and/or numbness in any oral area, you should take immediate action by consulting a dentist straight away.
Dental cavities and tooth decay can be very misleading, as they can take place due to many hidden reasons. Examples include Gingivitis, infection, ulcer, oral cancer and many more.
An infection or decomposition if left untreated can lead to several complications. So consult a dentist if you even get the slightest hint of tooth decay, cavity, or above mentioned symptoms and signs.