Hi everyone. I took Sunny to the vet today and the vet gave him a cortizone injection. The vet wasn't too worried about it. He said that it could have been caused by one of my other cats scratching him during rough play or it could be allergies. I asked him if it could be a reaction to advantage since this is the same area where I put it on him. He said he didn't think so because it was a week ago that I had applied it. The cortizone shot lasts four weeks so I'll see how he does after that. He's still acting normally so I'm not too worried. The vet said that if I wanted to clean the sore that I could use peroxide or some other product(I forgot the name). He said the best thing to do is to leave it alone. I sure hope that it heals fast and doesn't reoccur. Thanks for everyone's concern. Sas, yes Sunny is half aby. The vet also has told me that he has a lot of tartar on his teeth. He's only 2 years old. I guess he'll need his teeth cleaned next.