Water resistance is not a permanent condition and over time seals deteriorate. The best thing to do is to open the device and see how much water got into the device. Cleaning everything inside with 91-99% isopropyl alcohol and letting it dry is the best way to deal with water entry but, most likely damage is already done. The phone will start acting wonky if it's damaged. If you don have the know how to disassemble the phone you'll need to take it somewhere that has experience is water damage