welcome in H.C.M.
I have gone through your query regarding swelling of parotid gland
and at the same time there are lump below the ear in neck. You are also having red and swollen eye and you are now developing the on opposite side even after taking antibiotic.
Regarding your first question I would like to tell you that parotid swelling in your case is most likely infective may be viral or bacterial because you are now developing same lump on the opposite side as well which is possible in infective lesions only not in neoplastic (tumors).
Your lump below the ear is most likely enlarge lymph
node because of parotitis
. As far as diagnosis is concern it is mainly clinical i.e. by examination but confirmation is by Ultrasonography
of parotid region and FNAC from parotid and from the lump in neck.
Regarding your second query I would like to tell you that ophthalmic branch of facial nerve
passes through parotid region therefore it gets involve in such swelling and giving problem in movements of eyelids and developing red eye.
This is not a serious infection usually self limiting , you are already taking antibiotic now you may add anti inflammatory as well.
I hope your query is now answered.