Why is my iPhone overheating and charging slower?

Hello , I think I may have gotten moisture into my bottom right speaker about a week ago now.

Well , with intentions of " just opening up and seeing what's inside and if its damp or dirty wipe it off" and with no prior research of the battery compartment , I thought that the battery would come right out like any cell battery.

I noticed that it was attached and that it still powered itsself back on while I had the battery lifted out with one finger. I gave the battery a good look over, twice, and then replaced the back.

Since then my phone has charged 100% one time and it took all night. It's been overheating especially while its charging. And also dying fast. What did I do and what can I do. Please. Thank you !