The fact that you've already turned it on may mean there's nothing anyone can do. Water doesn't hurt your iPad as much as the short circuits caused by the water.
stop using it. Put it in some dry rice for a few days. you may need to charge it when you take it out but the rice will help wick the water out of your device. It'll work or it won't.
If it is irreparably damaged your main option will be to look at an out of warranty replacement, which starts at 219 and goes up from there depending on your model. If you happen to have apple care plus then you can use one of your allotted incidences of accidental damage replacement, which carry a smaller fee.