Hi,
If you suspect water damage then presumably the phone has gotten wet at some time. Is this correct?
If so, then the only way to verify if there has been water damage or not is to open the phone and visually inspect the internal components to see if any water damage has occurred.
I also recommend that you stop connecting the charger to the phone until it has been inspected.
Normally when an electronic device has been affected by water the first thing to do is to disconnect and remove all sources of power, i.e. the internal battery and external sources, to minimize any further damage.
Here’s a link to the ifixit [[Electronics Water Damage]] guide which may be of some help.
Here’s a link to a [https://www.youtube.com/watch?v=KM2J2Ea1avo|video] that shows how to replace the battery in the phone. I realize that this is not the problem but the video is useful as it shows how to open the phone so that it can be inspected.
There are other videos on YouTube that show how to replace the screen etc, on you model phone which may also be of some help in gaining access to the various parts of the phone.
If doing this seems too daunting a task, contact a reputable, professional mobile phone repair service (preferably experienced in liquid damage repair) and ask for a quote to repair the phone.