A 48-year-old woman presents to a community health clinic complaining of recurrent episodes of unilateral eye discomfort, redness, and sensitivity to light over the past several months. She reports that the current episode, affecting her right eye, began three days ago with a foreign body sensation and mild tearing, which has progressively worsened. She has a history of similar, self-resolving episodes, but this one feels more intense. Her past medical history is otherwise unremarkable, and she takes no regular medications. On examination, her visual acuity in the affected eye is 20/40, while her left eye is 20/20. The conjunctiva of the right eye shows diffuse injection. Slit-lamp examination, after topical fluorescein application, reveals a branching epithelial lesion with terminal bulbs on the cornea. Her temperature is 36.8°C, blood pressure 128/82 mmHg, pulse 76/min, and respirations 16/min. What is the most likely diagnosis and the recommended immediate therapeutic intervention?