A rock flew into my windshield and I have a couple of nice pitted spots on my windshield. No penetration into the glass, only superficial damage

 

you can make it a bit better by rounding the edges, but cant really fix it as far as i know.
everything that i have tried has not worked...
unless there is something newer that i am not aware of, filling is not a permanent fix and usually looks bad.
check with your insurance co- a new windshield might be covered (usually is if a crack develops- like you said, need a bigger rock!!)