It is just a really minor scratch. A watch with scratches is a watch with character. Don't bother about it. My pal has a Rolex submariner with tons of scratches and it looks really cool and rugged on his wrist. Tags are watches for machos, it is meant to have scratches.
If the scratch is on a polished surface, you can remove it with Silvex (you can get a tube from that watch accessory/part shop at Jalan Sultan Selangor Complex next to the hotel, just beware of the unfriendly women (wo)manning the counter). But in your case, the scratch is on the brushed surface and using silvex will alter the brushed surface. You probably need to get a grey polishing bar for it but this needs to be handled by a real expert.
If I were you, I'll just leave it as it is.
