hello & welcome
on the basis of symptoms you are presenting here this could be a mucocele
Mucocele is a fluid filled cyst
usually occur under the tongue because of blocked secretory glands & get bursted without any pain. The fluid released may cause sticky feeling.
no treatment require for this unless until you feel pain or area get infected, this cyst may reoccur very frequently.
you have to maintain adequate oral hygiene
with 0.12% chlorhexidine
mouthwash and warm saline rinses.