What should you know about an infected swollen lip?

Infection can enter through a split, bite, cold sore, piercing, dental problem, or irritated skin. The lip may feel sore and tight, with crusting, pus, spreading redness, or swollen nearby tissue. Swelling can also have non-infectious causes, including an allergic reaction or angioedema; sudden swelling without obvious skin changes should not be assumed to be an infection. A clinician may examine the mouth, teeth, skin, and lymph nodes to identify the source.

Keep the area clean and avoid squeezing, picking, or puncturing it. Wash your hands before touching the lip, do not share lip products or towels, and pause irritating cosmetics. Drink fluids and choose soft foods if movement hurts. A healthcare professional may recommend treatment directed at the cause, such as an antimicrobial medicine or dental care; do not use leftover antibiotics or someone else’s medicine.

Seek urgent help for trouble breathing or swallowing, tongue or throat swelling, rapidly increasing swelling, faintness, or widespread hives. Arrange prompt medical review if fever, severe pain, pus, spreading redness, a dental source, or difficulty opening the mouth is present. People with reduced immunity or poorly controlled diabetes should seek advice early.

Ask what may have started the swelling, whether the mouth or teeth are involved, which treatment is appropriate, and how to protect the skin while it heals.