In addition to Phatch's comment that some foods tend to cause that, it is also caused by using metal utensils. Were you using a metal paddle? I do, and I see that kind of minor scratching (or whatever you want to call it) every once in a while. But it is generally just an "appearance defect" and doesn't really impair future use of the wok. Whatever you do, don't rush into any re-seasoning unless you are absolutely sure that is required. Based on your pic, it is not.