Better be safe and order a new lens cover; It is only $5.99 on the ifixit market place. The glass is adhered so you have to push from the inside out to get the glass off then re adhere the new one in place. Best to use heat to loosen up the adhesive.
Try holding down the power button long enough to hear two beeps. This causes the display settings to reset and switch between composite and HDMI. Otherwise, you can download an PUP file from the official Sony support page. From there you can use a USB and reinstall the operating system. If it's not turning on at all, that likely lies within a hardware issue that may be worth forgetting about.