I too about 2 months ago was hit by a good size rock, I was going about 70 mph. when it hit. It gave me a star about the size of a nickle too. Just to the left side of the rear view mirror, almost in my line of site. So when I got home I got out the repair kit and filled the star with the epoxy from the kit. I've used it on other small stars with good results, they didn't spread. So 2 months later and its still all good. The kit didn't cost much and my Insurance co. doesn't do repairs anymore(State F). So if you need to fix a chip. Give the repair kits a try, I got it at Kragens. One tip to using the kits is use a hair dryer and warm the inside of the glass after the epoxy is applied, to draw it into the chip.

 

I was surprised to not see him fill the chip the traditional way.
They have a cool battery operated machine that goes on the window that sucks the air out of the crack, then it applies the epoxy, then he uses an infrared device from that machine to cure it.

Took him less than ten minutes, and also inside of the window was a mirror suction cupped to the window so he could see the progress from outside.

He said only Safelite has this machine, an employee designed it.

All I can see now is a spec, I can live with that.
Good thing I got it repaired, as the last chip grew into a crack all the way across last time.
A few days had passed though.

 

Mine has taken some great blows, but the only thing to cause any damage was the half brick I hit doing 75 mph and the meteor that hit me.