? If it is right at the top, could she be scraping it against something that she is squeezing in and out of? Is it always in the same place? 
Hello, sorry for replying a month after your post... But my cat with IBD gets similar sores occasionally, mostly on the back of the neck. They seem to be caused by allergies or food intolerance. It's often the first sign that he is reacting to something in his food and can sometimes progress to a full IBD flare-up with vomiting which needs steroids. In his case it's usually fish, or some of the lower quality foods with animal/meat derivatives (which he unfortunately likes
). Who knows what's in there! Nothing much seems to help applied topically, other than adjusting his diet and paring it down, removing all possible rubbish ingredients and feeding simple good quality food e.g. home-made when time allows. I'm not sure if this helps you, but at least you have a probable cause. 
Yes, its on top of her head, its usually the same spot although rarely it can be under her chin, which i assume happens when she scratches herself with her claws and she doesn't let me cut them at all. When i do she actually gets mad at me after it. I will also watch out for the food allergies, she is very picky and eats the same 3 brands of wet food. Now that its been a month the scab is almost completely gone. I hope it doesnt happen again but if it does I'll definitely try the chamomile tea. Thank you for your help!It could be from a food allergy That often causes itchiness about the head and/neck. From the angle of the picture, I can't quite tell exactly where on her head this is...kind of looks like the top, but I don't see her ears
Here is an article about different skin conditions that could be helpful: Skin Conditions In Cats - TheCatSite
In the meantime, you could try using some chamomile tea to see if that help relieve her. Just tea bags from the grocery store. Brew some up, let it cool, then apply to the wound with a cotton ball. You can do this a couple times a day. At's antibacterial and antifungal .
