Grey triangle with thermomiter

A

AC Question

When i plug my s6 in to charge it shows the battery charging then flicks to a grey triangle with a thermomiter inside it, what does this mean?
My partner dropped it in a puddle and we've had it in the rice/warm place for 2 days and was told to plug it in after to see if it had worked, its obviously not completly gone because these things show up but it was just wont turn on after this.
Thank you in advance!