As its a surface rust spot ,the Best repair you can make without resorting to a spray can, and will take seconds to complete id this way
1st find out exactly what the Colour code of your car is May have to visit a dealer for a number
Though all you'll need will be found in a Shop which specialises in car paint or in a Motor factor store (bit of a basic range)
And They will have a Colour chart to get a Near match and Mid range colours Reds/Blues & Greens are very Difficult even with 100% colour vision Dont go in asking for a Blue (It does not work like that) I fell into that trap asking for Island Blue when the correct shade was Island Blue No 2!

But the good news if your car has had a respray (and a runaround) the shades won't match Just trust your Luck
Here is what you need for a job as good as the garage
2 sheets of emery Paper of cloth 1 can be "medium grade" if the rust is bad "Fine grade " if its Light rust
Rub it down until the rust has gone and you can see bright metal (will look like a bullseye)
The other emery Paper/sheet is graded "wet & dry" Paper and is very fine I'd wet sponge the "bullseye" ans wet the Paper rub the "Bullseye" for a few moments then Dry the Area How does it look now? (really defined?)
Now the Paint issue Are you good at "rub on' transfers? Many Motor factor/Paint shops sell Sheets of car Paint transfers in Many shades Hence me asking about that issue
and you cut them out and rub them Down ...The lazy ones will not do any prep work Hence rust starts to creep and the Repair patch is stuck on top of a New rust dimple

PS It does help if you Mask the Work area with Newspaper and Paper tape
Note that there are several ways of doing this Job
Here is the
Readers Digest way with Rubbing compound (which is a Bit kinder on a small Non rusty chip)