Screen not responding to touch

I found this 64gb itouch at a restaurant and the screen doesnt respond, I reset it and still no luck, tried reformatting and it still doesnt respond, so I bought a new screen assembly with the touch sensor in it, when I went to install it and I had the old one off I noticed that there was damage to the circuitboard at the bottom behind the home button location. Is this board replaceable? I cant find out what this part is and it makes it difficult to price, but it definitely is the problem because a few diodes are corroded with water damage and they have burst, regardless if they are actually diodes or just some other component they are still messed up. Does any1 know what this board is and what it controls. For a recap, the screen turns on, but you cannot unlock or turn it off due to no screen functionality. It connects to computer fine but wont respond to touch. I tried installing my new screen assembly but it still acts up. Any knowns?