A 50-year-old healthy woman presented with four days of high-grade fever and left-sided headache followed by one day of left droopy eyelid. Symptoms developed two weeks after an outdoor summer trip to Massachusetts with exposure to insect bites. Her neurologic exam demonstrated 2mm left-sided ptosis, miosis with a briskly reactive right pupil from 6-to-2mm and left pupil from 3-to-2mm in the dark, and 2mm-difference in pupil size in the light with a smaller left pupil. She also developed macular patches over the head and trunk consistent with multifocal erythema migrans. Initial laboratory work-up showed mild anemia, thrombocytopenia, and elevated transaminase levels. MRI of  brain and orbits with contrast revealed asymmetric enhancement within the left cavernous sinus and superior orbital fissure with mild edema of the left extraocular muscles. MRA/MRV did not show evidence of cavernous sinus thrombosis, carotid-cavernous fistula, or other abnormalities. Cerebrospinal fluid analysis showed lymphocytic pleocytosis with negative Borrelia species detection by PCR. Further testing revealed elevated serum total Lyme antibody and Western blot IgM suggestive of Lyme neuroborreliosis. Patient was treated with oral doxycycline with resolution of symptoms.