What should you know about one lip swollen?

A single swollen lip can appear after biting the lip, a minor knock, a new lip product, dental work, or contact with an irritating food. A tender, warm area or a nearby sore may point toward inflammation or infection. Sudden swelling of the lip, tongue, face, or throat can occur with angioedema, which may be triggered by food, medicine, or another exposure.

The appearance alone cannot identify the cause. Notice when it began, whether it is spreading, and whether there is itching, hives, pain, fever, drainage, or breathing trouble. Angioedema is a useful related topic to discuss with a clinician.

Stop any newly used lip product and avoid foods or medicines that seemed to precede the change until a clinician advises you. A cool, clean compress held gently against the area may ease discomfort. Do not puncture, squeeze, or apply strong creams to the swollen tissue. Keep a note of exposures and take a photo if the shape changes; this can help a clinician compare progression.

If the swelling is mild and settling, arrange routine medical or dental advice if it does not improve, keeps returning, or is accompanied by a persistent sore or tooth pain.

Seek emergency help immediately for trouble breathing or swallowing, a tight throat, a hoarse voice, tongue swelling, dizziness, or rapidly spreading swelling. These symptoms can signal a serious allergic reaction. Seek prompt medical assessment for fever, pus, severe pain, marked redness, or swelling after a significant injury. Do not drive yourself if breathing symptoms are developing.

Ask: Could this be an allergic reaction, infection, dental problem, or irritation? Which warning signs should make me seek emergency help? Should I stop a medicine or product? What examination or treatment is appropriate if it returns?