Low sound from inner earpiece after water/oil

Hello.

Two days ago, some drop of water and oil covered the glass of my iPhone. It's not a full immersion, but earphone was totally covered by liquid.

Yesterday I tried to do a calling, but the sound from earpiece is very low and the only way to have a conversation is to plug an earphone or to activate speakerphone (vivavoce).

I'm deciding to repair it by myself. Which parts are probably damaged?

I was thinking to buy earpiece, metal clamp and sensor flex.

It could be rights part to replace?

Many thanks