The hood of my car seems to have taken a nasty rock hit. I'm not sure how deep the damage goes but I'm going to touch it up using a paint pen. How long do I have before oxidation starts if by some chance it is down to the bare metal? The soonest I can get a paint pen is next week (dealer has to order it).

 

All hood have rock chips. Most don't rust visibly. Don't worry about it, you can sand it before touching up anyway.

 

maybe you should take an total repaint of the hood, i dont know how your cars paint seems overall, but if its not to bad it wont shine up to much compared to the rest.

I just did that on one of my sides, its not noticeable that it repainted!