"Scratch" on my cat's head?

Keep calm, it looks like (almost) nothing.

Is it bad? No, don't worry. It's barely a scratch at all.

Should you go to the vet? No, not unless one of the following happens:

• The area gets swollen or bleeds strongly or changes color. (Note that the small red spot is no blood, but wound secretion)
• Your cat drastically changes her behavior, stops eating, drinking or defecating or gets lethargic.
• She scratches so much that the area gets bigger or she scratches other areas of her body.

What could it be?
Maybe she misjudged the distance while playing and smacked into a corner, maybe she tried to squeeze into a too small hole, who knows. The only possible cause that requires your intervention is parasites like ear mites or fleas. When cats have itchy ears, they scratch the skin right in front of the ear instead of inside the ears, which causes bald spots and wounds in that area. Just keep an eye on her and see if she scratches herself very often. If yes, consult a vet.

Please be aware that healing wounds itch as well, so she will be scratching that spot for some time until it's healed. She just shouldn't scratch so much that the spot grows bigger.

Overall, she looks very healthy and doesn't make the impression of having parasites. Simply give her time to heal.