Oral piercings can be bad for your health. Because your mouth contains millions of bacteria, infection is a common complication of oral piercing. Pain and swelling are other side effects of piercing. Your tongue (a popular piercing site in the mouth) could swell large enough to close off your airway. Piercings can also cause uncontrollable bleeding or nerve damage. The jewelry itself also presents some hazards. You can choke on any studs, barbells or hoops that come loose in your mouth, and contact with the jewelry can chip or crack your teeth.