IPhone 4 water damage. Sound works but is not an option?

I stupidly dropped my iPhone 4 in the toilet today and I immediately wiped it off and put it in a bag of rice. After about 5 hours I took it out and it was working fine except there was no sound. Then I started to panic. I opened Settings and under Sounds I played with the ring volume. Sound came out of the phone so I stopped worrying but then I noticed that the volume buttons do not work but ring/don't ring button slider thing does work. Also, in the Control Center (the thing you pull up from the bottom of the screen) there's no volume slider and in Music the volume slider is grayed out and you can't touch it. The music says it is playing. Please help! DIY options would be amazing because getting a new phone would be really difficult and I'm leaving for a summer thing in 4 days and I really need my phone! Any help will be appreciated!

I think you should consult with the mobile mechanic.