Ringworm after getting nuetered?

I got my 1 year old cat neutered about 3 weeks ago, and during these last 2 days I have noticed this thing on the back of his neck. There is hair missing, and its shapped like a perfect circle, about a little smaller than a dime, and their is some hair in the center of it. Seems to perfect of a circle and then a perfect patch of hair in the middle to be ringworm, right?
Is that were the vet would do some type of injection or something before they did the neutering, or does it sound like ringworm? The color of the skin were the round patch of hair is missing is white. Any advice? thanks

It does sound a lot like ringworm. To be sure, it's best to take your cat to a vet where they can examine the spot and give you the right treatment.

It really sounds like ringworm. You need to have him see the vet just to be sure.