Something bit my lip and now it is swollen

A bite can cause a small area of inflammation, tenderness, redness, or itching where the skin was disturbed. Swelling may also reflect a reaction to saliva, venom, food residue, or another trigger. Angioedema is deeper swelling that can affect the lips and may occur with hives or swelling elsewhere. The appearance alone cannot identify the cause.

Look at whether the swelling is staying local or spreading. Note any puncture, blister, warmth, drainage, fever, or worsening pain, since these details help a clinician distinguish irritation, allergy, and infection.

Rinse the area gently with clean water if there may be residue, then apply a wrapped cool pack for short periods. Do not scratch, squeeze, or apply household chemicals. Keep food and drink away from a broken area until it settles, and choose cool, soft foods if chewing is uncomfortable.

If itching is prominent, ask a pharmacist whether an antihistamine is suitable for you, especially if you take other medicines or have a medical condition. Photograph the swelling and record when it began and what may have caused the bite.

Call emergency services immediately for trouble breathing, wheezing, throat or tongue swelling, difficulty swallowing, faintness, confusion, or rapidly spreading swelling. These can signal a serious allergic reaction.

Seek prompt medical assessment if swelling keeps increasing, the wound is deep, pain and warmth intensify, pus appears, fever develops, or the bite involved an unfamiliar animal. Arrange a review if the swelling does not begin to improve or repeatedly returns; a clinician may assess for angioedema.

Could this be a local bite reaction, angioedema, or an infection? What symptoms should make me seek emergency help? Is an antihistamine or another treatment appropriate with my health history?