Water Damaged Iphone Hissing sound while wireless charging

I accidently dropped my iphone in water. Nothing weird happened except for the liquid detection warning when I tried to charge it, so I unplugged and followed advice of having the connector facing down while using my portable battery to charge. It was fine for 30 mins or so and then started to have a hissing sound, which stopped as I took away the portable battery.

My question is: is using portable battery safe? is it safe to use wired charger again as long as there is no warning? or do i need to get it repaired asap?