In order to determine if the inflammation is coming from Sjogren's they would have to see actual infiltrates. Even in a lip biopsy they might see inflammation, but that is not enough for a diagnosis. They must identify infiltrates (and a certain amount) of lymphocytes, histiocytes and plasma cells for a diagnosis.

Apparently in order to determine if this is coming fro Sjogren's, you'll need the lip biopsy.