Yes backfire and after-fire create an amazing amount of excess pressure on an exhaust system and 1 or more of these can and will destroy the exhaust system.
Almost all vehicles '90 give or take and newer are quite sensitive to exhaust leaks, lose of back pressure, o2 sensors not coming up to or maintaining temperature and sending the ECU into a fault mode that allows the vehicle to run rich (a little extra fuel for the same amount of air) for over heat protection and the fuel economy and power suffer.
Not to mention the CO2 and other noxious gasses that might find a way into the interior space is amplified,,,
VERY UNHEALTHY. GET YOUR EXHAUST inspected and fixed asap