He is suffering from Mucocele of Retromolar trigone.
Mucoceles are painless, asymptomatic swellings that have a relatively rapid onset and fluctuate in size.
They may rapidly enlarge and then appear to involute because of the rupture of the contents into the oral cavity or resorption of the extravasated mucus.
Answered2022-06-17 02:03:45
Let others know if this answer was helpful