I just bought a used iphone. Worked fine until i got it home and it started not recognizing all my input. Then I got to peering and noticed two tiny pry marks. I work on cell phones and laptops so I can tell the faintest signs when someone didn't do a perfect job. So either glass or digitizer has been replaced. What could be causing it to drop input like this? It comes back after about 20 seconds. I'm sure it's not software since hardware and videos still work.? Can I fix this by just redoing his shoddy job?