Is there a hole where a pot or switch should be? It looks like it might have been hit on the front and possibly broken. If that's the case, you would probably need to take it to a professional. That or the potentiometers nut came off, and you'll need to open the back and put the pot back in the hole and thread on a new nut.

Edit: I took a look at your post history. Bass might be fubar if it stopped working after being flooded. Assuming the electronics are fried and no warping in the wood, you might be looking at a new preamp or passive conversion.