dear friend ,
thanx, for sharing your concern,
your history suggest ,RANULA
in the floor of the mouth , it is caused due to obstruction to the sub lingual salivary gland
and adjacent minor salivary gland .
sometimes, there could be a polyp which has developed there.
it could also be the result of chronic cheek biting
in that area.
could be gingival over growth or sometimes a gum boil.
all these are differential diagnosis,
exact evaluation can be made after clinical examination only(palpation, percussion).
an xray should also be taken to see underlying pathology then accordingly it can be managed.
hope this helps,