Hello,
From the symptoms it sounds like a ranula or mucocele. Usually it goes away on its own.But if it does not,then corticosteroid injections and surgical removal by scalpel or laser are done by a dermatologist.It then has to be differentiated from other mucocutaneous lesions also.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.
Mostly a mucous cyst,nothing of concern.Would resolve, if persist do consult.