There are some tricks where people put grease into the scratch or use a small pencil eraser to remove it. But no matter what you are degrading the lens and may remove anti glare coating. There is no fix but replacing the lens, which may cost more than the camera.
I have an action camera with a scratched lens, and uses it as a secondary camera or backup. The kids are also allowed to play with it.
It is a shame when it happens, but if you use your equipment it may get damaged. But a damaged camera that has taken a lot of awesome pictures is much better than a camera in perfect condition you never use.