hello and welcome to hcm forum Ema,
according to the dental history provided by you , i would like to inform you that you dentist
was correct when he said that the lump is due to salivary gland
you have not mentioned anything about your medical history, i assume there is none.
also, is there any dryness of mouth?, this is a very common symptom from swollen salivary gland.
i would advise you to visit an oral pathologist as a few tests might be required to rule out the cause and provide you with the treatment.
try to drink lots of water, do not take anything spicy.
kindly visit your dentist soon.
i wish you good health,