tooth needs to be re treated.
Welcome to HCM,
According to your history I can suspect some remnant of the infected pulp tissue has left unexplored during the root canal
procedure or there is a missed canal due to which the infection has gone worse and you have developed a periodontal abscess
due to spread of infection to the underlying tissues.
This type of periodontal abscess drains in the oral cavity and may lead to nausea and vomiting.
This type of periodontal abscess needs to be drained and compressed in position and then followed by a course of antibiotic and analgesic will subside the symptoms of pain.
once the abscess is drained the infected tooth needs to be explored again for root canal procedure.
I would suggest you to get an OPG radiograph done for your tooth which will help in diagnosis accordingly the bridge can be removed ,tooth is disinfected again and the bridge is replaced again at place.
Meantime I would start you on amoxycillin clavulanate
and ibubrufen twice a day.consult a dentist
and get the treatment done.
I hope this helps,