hi, The condition got to be taken care of immediately!Reason being you are suffering fram a condition called carious exposed lower first molar with intra oral sinus
.the condition can trouble you at any given point in time.The symptoms can be sudden pain, sudden swelling ,trismus(inability to open mouth) or pus may start coming out of cheek externally.Long standing cases as of yours may also result in osteomyelitis
a condition in which jaw bone gets eaten away (potentialy dangerous) and at last there is always a chance of bacteria running in your blood(bacteremia
) so why to take chance go to your nearest dental surgeon and get an x ray
done the dentists would suggest either an R C T or Extraction of the tooth . hope it helps you !