I've never found that touching up works. The reason is simple. Unless you have identical paint material true colour match is impossible. The standard way to show this is to look at a patch in daylight, fluorescent tube light, and standard indoor lighting. It is not possible to match all three unless the material is from the original batch of paint. Even a different batch will show slight differences.

It's not just the colour, it is also surface finish.

How you repaint depends on surface quality. The photo attached clearly shows pitting. I will not be able to have this frame stove enamelled as it will need pitting to be filled. I could lead fill, but this is a very slow process. However, I have successfully resprayed far worse using auto spray cans. I have moved on to using a compressor spray gun, because it is less expensive but cans are fine, and I can get custom colours whenever I want.



The damage on your frame looks slight, and after shotblasting there is unlikely to be any pitting