If theres billions of bacteria in our mouths, how come when we cut our inner lip we’re not guaranteed an infection?

Question

If theres billions of bacteria in our mouths, how come when we cut our inner lip we’re not guaranteed an infection?

In: 85

Answer 1

Your immune system for one. It’s what it is for after all.

Another is that not all bacteria in your mouth are necessarily the type that will cause an infection.