You have an impacted third molar tooth. The condition is known as pericoronitis
. It is an inflammation of the gums around the tooth. You have to get an OPG xray taken and your dentist
can identify the actual position of the tooth. If the tooth is angulated it will have to be removed surgically and the problem will get resolved. Use salt water gargle 4-5 times a day and consult a Oral and Maxillo-facial surgeon at the earliest.