How do I fix my iPhones volume?

Okay, so about a month ago my iPhones volume started to not work. I would try to turn up the volume but it wouldn't go up. After about a week, something else happened. When I turned down my volume one bar, it would then turn down all by itself! Now, both volume buttons are not working and in order to listen to a Youtube video/ music I have to keep my finger on the volume bar on the screen to keep it from turning down or up by itself.

I have had a few baths in which I brought my iPhone in but I have made sure it hasn't gotten wet, however a few drops of water fell on the screen and possibly onto the volume button or something. And yes, I have stopped bringing my iPhone into the bath...

Help please? :)