Best thing to put on cold sores
Cold sores are treated with comfort measures and, when appropriate, an antiviral started early; avoid picking or irritating the blister.
The short answer
For a typical cold sore on the lip, use a clean protective barrier and ask a pharmacist or clinician whether an antiviral treatment is appropriate, especially early in the outbreak. Do not pick, squeeze, or apply harsh chemicals to the blister.
What causes the fluid-filled blisters of a cold sore?
A cold sore is a cluster of fluid-filled blisters caused by herpes simplex virus, usually at or around the lip. It can begin with tingling or burning, then crust as it heals; a sore inside the mouth may instead be a canker sore or another condition.
How can you protect a cold sore while it heals?
Wash your hands after touching the area, keep it clean, and use a plain lip balm or petroleum-based barrier to reduce cracking. Avoid kissing, oral contact, and sharing cups, utensils, towels, or lip products while the lesion is active.
When should a cold sore be examined by a clinician?
Seek an examination if the sore is severe, recurrent, spreading, unusually located, or not healing, or if the diagnosis is uncertain. Prompt medical advice matters for eye symptoms, extensive lesions, or a weakened immune system.
What should you ask if the lesion may not be a cold sore?
Ask whether the lesion looks like a cold sore, canker sore, angular cheilitis, or another problem. Ask whether an antiviral is suitable, when to start it for future episodes, and how to reduce transmission to household members.
Frequently asked questions
Can I put toothpaste on a cold sore?
Avoid toothpaste and other irritating substances on the lesion; use a plain protective barrier instead.
Is every lip sore a cold sore?
No. Canker sores, irritation, angular cheilitis, and other lesions can look different and may need different care.
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Who wrote this page
This library is published by Dental Nation, a licensed dental group practising in the United Arab Emirates. Pages are written and overseen by the same clinical team that treats patients in our clinics, and are held to a fixed editorial standard for safety and accuracy.
This page is patient education, not medical advice, and cannot replace an examination. Anything urgent — facial swelling, trauma, uncontrolled bleeding or severe pain — needs a dentist or emergency care now.