My new baby has received her first injury: I didn't properly tighten the quick release on the rear wheel after fixing a flat, and the wheel slipped forward in the dropouts while I was at traffic lights. No injury to me, but I've taken a chunk of paint off the corner of the dropout.

Now if I'm correct, steel is inclined to rust, and exposed steel on an otherwise-painted frame will start to rust first. I'm supposing, therefore, that leaving this patch of naked metal is a bad thing.

Do they make touchup paint for bikes? Should I just go get myself some of the white touchup paint they use for touching up whitegoods (it's a pearl-painted frame)? Is this not worth worrying about?