Hmm, well if it was charging when it got spilt on, then there's a very good chance that the battery (possibly the controller too) did get fried because water + active electric current = death for electronics. Since you did try to turn it on when it was most likely still wet it's probably dead. What I would do is still try to save it via rice, possibly even silica packets if you have them lying around. Do that for about 24 hours. Other than that you can void the controller warranty (if it still has one), and replace the battery.
Here's a guide for it: [guide|22074]
Here's a battery: [product|IF297-035]
If still no luck, see if Gamestop will take it. But from what I remember working at Gamestop, if it doesn't turn on, we don't want it.