First and foremost: after receiving water damage, is not wise turning a device on.
Actually the water isn't responsible for damaging devices, but electricity is: water reroutes electric impulses were they're not supposed to go, making the device go crazy.
To avoid further damage, you should let the device dry perfectly. Using a Thirsty Bag is the safest course of action, lacking that, a dry cupboard with a cup of silica or (lacking that) rice is helpful.
If you're skilled enough, and you were planning already to do that, open your device, clean it with some isopropylic alchol and let it dry throughly. Otherwise, you may seek the help of someone capable. A severe water exposure may leave droplets of water hiding in every nook and cranny of the device, and they may be hard to remove by a mere drying.
When the device is dry and clean, you can reassess the damage.
If you need help with the opening, I can see there are some guides here on iFixit.
You also say that you don't know if it got wet or not... you should assess it properly.
Re-evaluate the device when it's completely dry and clean, don't attempt to make it work unless all water has gone.