Rust!

hello, I have a 61 impala in near mint condition but recently some rust has appeared under the left front headlight. What is the best way to take care of this and stop it from spreading? Is there any kind of spray or anything that is easy to use, because I really dont want to have any major work done around the area since it has a custom paint job in the front end. Any help will be greatly appreciated. Save her from the rust!