More information needed.
The must important thing to ask you is your age. I would be more worried to know why the heck does that tooth fell. I lived with a dentist for almost 6 years and i had learnt something. There is no reason a healthy person should loose a tooth.
Yes the hole can get infected. If the tooth didn´t fell completely there can be pieces of the roots still under the gum that can produce nasty infections. So ask your family or peers for a trustable dentist.
On the meanwhile clean brushing the area gently with a little bit of paste, ingest mostly liquids and soft, and do not hear to any alternative or naturistic treatmets. GO TO A DENTIST.