Cat is drooling,tongue is out,white spots on tongue and inside of mouth,

First of all how old is your cat? Is he/she indooors/outdoors or both?
Are there things around, chemicals etc. that he/she can get into?
My top guesses,
Your cat has gotten into something caustic that is irritating the mouth and tongue, if this is the case it will likely not get better without some help from your vet.
Or,
Your cat has some sort of infection that is causing the delicate tissue to ulcerate, in which case still needs to be seen by your vet.
These are are only guesses on my part, but the fact is that whatever is going on may cause her to not want to eat or drink, and this is no good for a cat.
Better to find out early on what the problem is and not let her make her self sick because eating and drinking is painful.
Good Luck and keep us posted.

One more poossibility that I can think of. Does your cat ever chew on electrical cords?
In which case still needs to see a vet, but is another possibility.

My vote is also with having chewed on an electric cord. Lucky cat, if so.

Sometimes the shock sort of 'scrambles' their thinking processes, for an indeterminate period. And, along with the tissue damage, may contribute to the salivation. The white spots are tissue areas directly affected by a current, and eventually heal but leave a bit of a scar as evidence.

Check for a mild sign of damage to any cords, often where kitty spends it's time. I say mild because if kitty got a good, relatively noticeable bite of the cord, that is where you would have found her/him... no longer with us. You may want to consider replacing whichever cord is damaged, if that is the real culprit here.

Having your vet see him/her is advisable since mouth injuries can be easily infected, in addition to possibly interfering with eating or drinking.