Cat help

[aria_s]

Our cat Spike has a wound like thing on his neck. It looked like it was scabbing over for a while, but now it looks worse, I think he has probably been scratching at it and keeping it from healing. Him and his sister have been fighting more recently and I think that is probably what initially caused it. How do we help it get better, and keep him from scratching it?
Any advice?
I've been kinda a worrywort about him since we had to take him to the cat hospital for something unrelated last month.