HI try and check via dialling *#*#66#*#* Service tests > Test Single > Battery status check > OK
You can do this whilst on battery then whilst monitoring > Plug in the charger as ‘Instructed’ at the bottom. This will show if it is registering.
The dampness can take more days to get out. Ensure you keep the phone in flow of air when not using if you can and even dismantle and allow more air in side.
You don’t say how you dried it. Did you dismantle the phone and look for the red squares, (dampness indicators) ?