Hi and welcome,
After reading your history i suspect there is infection of salivary gland
either it can be parotid gland
swelling caused by PAROTITIS
or there is some infection in the jaw bone leading to formation of a cyst
or an absces which protrudes extra orally.
i would suggest to approach a surgeon and get an OPG radio graph done which will show the exact cause, extent of cyst and its association with the adjacent vital structures.
Accordingly the cyst can be enucleated to remove the entire sac along with cystic lining surgically to prevent any reoccurences. or if it is parotitis it can be treated with medication.
i hope this helps,