Yup, just what Flashy said! Zeke is a castor, a dark skinned bunny. But if he had white fur or a fur colour that comes with light skin, his would have been much lighter.
If you bun looks like Zeke but just a lighter colour, then I wouldn't worry! He should be healed in no time.
Almost all of my neuters have come home and acted like nothing has happened. They still got pain meds, but they acted like they never had an operation!