Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Cold Sore and Canker Sore
Medically reviewed by Min Clinic Staff | Updated: January 2026
Picture of Cold Sore and Canker Sore
Cold sores and canker sores aren't the same. Cold sores usually appear on the lip; canker sores affect the inside of the mouth. Canker sores don't involve the herpes virus and aren't contagious. Their cause is unknown. Cold sores generally herald their arrival with a warning period of red, irritated skin. Blisters form, rupture, then crust over before healing.
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