Is the hole in the top ( roof) of your mouth or in the back on the side?
Here is a picture of a tonsil in the back of a throat.
Many times people get "tonsil stones" in there which is basically food, sinus drainage debris and smells pretty bad.
Even if you have had your tonsils removed the hole will still be there.
Try gargling with salt water to help get rid of them if you get more.
It is pourous so things will go through it.