A lump in the parotid gland may indicate salivary stones or a bacterial or viral infection in the gland, according to WebMD. Stones, the most common cause of swollen glands, are build-ups of saliva deposits which block the ducts. A blocked duct may also cause a bacterial infection.
The parotid glands are salivary glands located inside the cheeks, and bacterial infections are the most common malady involving them, explains WebMD. Pain is usually intermittent and on one side of the face. Bacterial infections can cause fever, pain, abscess and foul-tasting fluid to drain into the mouth.
Viral infections such as mumps or flu can also cause the parotid glands to swell.