Its very easy to get a scratch on the car. Even though it may be just a light touch, the mass of the car is such that the damage is always more.
Run your finger over it and see if the scratch can be felt t be deep. If its deep, there isint much you can do- get it fixed at the showroom. If its just a scrape, patch it. There are those 'scratch remover" pens that are available. They just fill up the top cote- the top layer of the paint. Unless it is just a scraping, the scratch will still be visible. However, the marker will reduce rust. Do it in bright sunlight though otherwise the fluid doesn't cure. AFAIK
, that's about all you can do yourself.
When you go to the showroom next time ask them to fix it