What's the cause of mouth sours

Canker Sores

No one knows what causes these small, painful blisters inside your mouth. Triggers include hypersensitivity, infection, hormones, stress, and not getting enough of some vitamins. Also called aphthous ulcers, canker sores can show up on the tongue, cheek, even your gums. They usually last a week or two.

Explanation:

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