Yes, as above rinse and dry out, theres usually no need to toss a light, the case cant get damaged with a bit of water and you can usually replace any internals that may need replacing, mostly the reflector and LED.
The secret when one has any flood be it a light or a computer or a camera is to get the batteries out as quickly, if its a full flood take them out right there under water if possible (dont leave them there though) then at the surface rinse thoroughly with fresh water, if its a camera immerse in distilled water, you need to get the salt out or it will dry on the internal parts (like salt dries on your face) and ruin it. Then dry it as much as possible, if you can put it in a pillow case for instance and allow warm (not hot) air from a hairdryer to blow over it for as long as possible or until your wife needs the dryer. Then buy some rice and pack the product in the rice, cover it completely (molecular sieve is better if you can get it but rice will do in an emergency) leave it for a day or two, or three, maybe four............!
Take it out and test, a light will easily be saved like this, even camera's and computers, cell phones etc can often be saved like this.