There is no water resistant phone, one brand try that, those phone resisted normal water, but not salt water, so they paid a lot in waranty, you just had bad luck, but maybe is only the screen that is bad, by the way, is better to put the phone in isopropil alcohol for a day and then let it dry for another day or two.(i did that with my sister phone, after that i took the motherboard and scrub the parts where i found corrosion)
In any case, you can know if the phone turn on by conecting it to a pc, if it conects after you try to turn it on then you have to replace the screen.