My cat has huge sores help?!:(

My cat is a year old and has a huge red scab on the back of his neck probably about 4cm wide and 5cm long so fairly big and he is losing his fur due to it, first of all I thought he has been in a cat fight and I have been trying to keep him in but now he has it below his ears on his face and just above his eyes two more sores which look like he has had a chunk of his skin ripped out and his fur is falling out in two strips along where the scabs are, he keeps trying to lick it and Im really worried, I have put anti bacterial powder for cats on his back but it is not healing, someone help please!

He definitely needs to see a vet ASAP. The first thing that springs to mind is ringworm, but it could just as easily be something else. We're not vets here, and certainly cannot provide a diagnosis. A vet check is the only responsible course of action. I hope its nothing major