Tooth problem and treatment needed.

Iam having tooth problem from two years.In my left jaw there was blakening between two teeth. The dentist drilled there and filled silver. But after 2 days the filling started coming out and there a hole is formed whatever i eat it goes there.I got my entire cheek area being swelled up from lower jaw to eyes .Its very bad swelling and intense pain is there from the mouth to the eye. and also a white pus filled boil appears on the gums above that tooth. whenever i eat from that side the same problem arises. its been two years i never ate anything from that side tooth .i am not able to even brush properly to that side which also resulted in heavy plaque formation. on the left side of the jaw that dentist extracted my second molar tooth . whatever i eat it it jst pricks over there so not able to eat any hard or crispy food as it result again in pain and swelling. Because of past bad experiance i am frightened to believe and go to any dentist and with 2 yrs struggling with this problem.