In general, most pineal lesions are pineal cysts and are benign. Studies estimate that as much as 25% of the population have pineal cysts. Also, bells palsy and pineal lesions are rarely connected. I would suggest seeing a neurologist if you're not already seeing one.
Sorry to hear of your diagnosis. What does it mean? Only a doctor reading your results can really tell you that but if it says mass it usually means a tumor. I have a pituitary tumor with cystic component and its something other than my pituitary gland that's present. Its funny they have many different names for the same thing - mass, tumor, adenoma..which can make it confusing - I know I was when first diagnosed. Hopefully, a doctor will answer you soon.
Be well