Judging by your description, it is most likely a fistula which is a tract that forms from the abscess of your infected tooth that escapes out to the gums. As long as the fistula in intact, your
abscess can drain and slow down the spread of the
abscess but if the fistula closes up, the abscess can spread rapidly through your face or neck area.
I would recommend seeing a dentist and getting treatment started.