2003 Pontiac Grand Am starter malfunction

My car will not start even though I have electrical and a good battery. I had to replace my starter last Spring due to water damage from flash flooding on my street from a rapid snow melt. It sounds just like that.A single click when I turn the ignition. There is no moan and groan as in a low battery. My son was sitting at a stop light in heavy traffic and his knee hit the keys and turned the car off while in gear. He turned it back on and the service engine light came on. We pulled off and turned the car off and then restarted it without incident and proceded on to Chicago and back home. Today, it will not start. Did he inadvertantly damage the starter?