Where do cold sores come from?

I have a small bump under my lip and hurts . I'm worried it's a cold sore. is it air born also? The only places I saw when I looked it up were from other people.
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+1 y
I've never kissed anyone before though , So I don't know how I got it.
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+1 y
It tuns out that it's just a blemish and that I am a hypochondriac .
Where do cold sores come from?
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