A boil under the nose is in a sensitive area called the danger triangle of the face. You must never squeeze or pop it, as this can spread the infection deeply. For immediate care, apply a warm, moist compress for 10-15 minutes, 3 to 4 times a day, to help it drain naturally. Keep the area clean. Because of the location and swelling, please see a doctor promptly. You will likely need prescription oral antibiotics or a prescription antibiotic ointment (like mupirocin) to safely clear the infection and prevent complications. If you develop a fever or worsening swelling, seek urgent care.