Thunderbolt phone with lines

I bought a phone used really cheap was dropped i believe crack across screen now pink lines on close to half of screen in pic as you can see. The seller says functional except the lines and volume down inoperable. Clean ESN. I was told by others on another forum could be water damage. But if not or if it is. Is there a work around for the vol down not working? Could i still root this and recovery or grab touch recovery? And flash rom off of phone and rom manager? Need help please