I have a 3" long hairline crack in paint on my rear bumper. It's so thin it's barely visible even if you're only a foot away. The paint is not chipping (yet). Is there anything I can do to prevent the crack from spreading and paint from chipping?
I was thinking of buying a clear coat touch up and applying it with a sharp toothpick. Would that work? I'm OK with it being there as it is almost invisible, I just want to prevent it from spreading.
Any advice is appreciated.
Thanks.

 

I would get that professionally refinished. The main reason is that it will lead to a larger crack in paint due to fluctuations in temperature (dependent on area). Also, you might have to consider environmental factors that can eventually lead to issues such as clearcoat failure.