When to worry about skin blisters with cold sores

Cold sores often begin with tingling or burning, followed by small grouped blisters around the lips or nearby skin. They may ooze, form a crust, and heal. The appearance alone cannot confirm the cause of every blister. A change to marked swelling, spreading redness, thick drainage, or pain that is out of proportion to the sore may indicate another problem or a secondary infection.

Wash your hands after touching the area and avoid picking the crust. Do not kiss, share lip products, utensils, towels, or razors while a sore is active. Keep the area gently clean and protect cracked skin with advice from a pharmacist or clinician. Arrange an appointment if sores are frequent, last longer than expected, interfere with drinking, or affect someone with reduced immunity.

Seek urgent eye care for a painful eye, light sensitivity, blurred vision, or blisters on the eyelid or around the eye. Get prompt medical help for a rapidly spreading rash, severe headache, confusion, fever with marked weakness, or sores in a newborn. A clinician should assess extensive mouth sores when swallowing fluids is difficult.

Ask whether the sore fits a cold sore, whether an antiviral treatment is suitable, and how to reduce transmission at home. Tell them when tingling started, how the blisters have changed, and whether the eyes, mouth, or other skin are involved.