A 25-year-old patient reports painful, fluid-filled blisters on the lower lip. Step 1: Physical exam shows clusters of vesicles on a red base (Herpetic Gingivostomatitis). Step 2: Diagnosis is Primary Herpes Simplex Virus (HSV-1) infection. Step 3: Treatment prescribed is Acyclovir cream 5% applied topically 5 times a day for 7 days. Step 4: Advise the patient to avoid sharing towels to prevent spread. Follow-up after 10 days shows complete healing of the epithelium with no scarring.