Periocular Swelling, Fever, and Organomegaly in a 4-Year-Old Child

A child aged 4 years presented with a 3-day history of worsening redness, pain, and swelling over the left lower eyelid and nose. Visual acuity was normal, and systemic examination revealed cervical lymphadenopathy and hepatosplenomegaly. The patient showed no improvement after 3 days of intravenous ceftriaxone, and a computed tomography scan showed a collection in the lacrimal sac. What would you do next?