Water Damage / Cable not certified

My daughter dropped my phone in water yesterday. I didn't know that she did because it was working fine all day until I tried to charge it. That's when she said "oh I forgot to tell you that it got wet this morning."

Though the phone works fine, it won't take a charge and I get this message on the screen when I plug it in (same message no matter which method I use to try to charge it): "This cable or accessory is not certified and may not work reliably with this iPhone." Can anyone help? Thanks!