Try a scratch-remover product. These are available online and in retail locations. Apply a small amount of the cream to the screen, then rub it in until the scratches fade away.
Apply pressure to the cell phone screen. Stuck pixels are another problem that can occur on a cell phone screen. They'll create discoloration in different areas of the phone. To fix this problem, rub at the discolored areas with a pen cap to disperse them on the screen.
Fill any cracks or scratches with a small amount of toothpaste.
Replace the cell phone screen. If the crack is severe, this may be your only option. You can search for your phone model and purchase a new screen through online stores. To make the replacement, use a screwdriver to pop off the old screen, then snap the new one into place. The process may vary depending on the model. When in doubt, take the phone to a cell phone repair shop to make the switch.