The radio in my 2002 honda accord works but the cd player does not. How do I get that to work again?

If the CD player stopped working, there is no magic cure. It needs to either be removed and repaired or replaced.

You can try using a CD/DVD lens cleaning disk. They're not that expensive and will clean anything that takes disks. TV DVDPlayer, internal or external PC optical drives, audio CD players etc. The main (time to buy a new one) failures are a burned out spin up motor or a laser lens failure. Can you hear the disk spin, does it make noises? If the track the laser slides on is sticking you might hear a clattering when it seeks the disk.