Scratch on watch

Cosmetic damage is not covered under warranty and glass can scratch, which is very common with wrist watches. To avoid future scratches and to likely hide the one you've gotten, put a screen protector on the watch. There are many options you can choose on Amazon.

If you want a watch in the future, which is harder to scratch, the Stainless Steel models and the Apple Watch Ultra, which costs more, do come with Sapphire glass, which is significantly harder to scratch.