Your first mistake was plugging the phone in to charge. That might have fried several components on your phone. You should have just opened the phone, placed in a container with rice and let dry naturally for 2-3 days before attempting to turn the phone back on or charging. Now, that these essential steps are no longer viable, try some damage control. Open your device and tear it down completely and clean with alcohol and soft toothbrush. Pay attention to areas with corrosion and clean that. Take your time and clean thoroughly. Let phone dry out naturally,
don't use any heat to dry the phone. That does not help, only makes things worse. After reassembling the phone keep your fingers crossed and hope that you have not cause permanent damage to the phone. Also, I can almost certainly guarantee that you are going to need another battery.