Wok clean up after every use
You are seeing oil polymerisation, otherwise known as seasoning. It is not required on stainless steel, but it can happen on its own under some conditions (a very thin layer of oil, or only a spray of oil mist, on a very hot pan surface) and wokking produces these conditions at least on parts of the surface. 

It is your choice whether to keep it or clean it. You won't be able to maintain a great seasoning on stainless steel, it will be somewhat patchy because it cannot cling as well as it does to reactive steels or iron. But since it is not functional on stainless, the quality of the layer is not really important. Just pay attention that it really stays a seasoning (made from burnt-on decomposed oil) and does not become char from carbohydrate deposits. 

If you decide to clean it, you won't get far with physical efforts or everyday cleaners. The more convenient way is to use boron based cleaners, but they are not sold in some parts of Europe due to safety and environmental concerns. The other way is sodium lye, which does not have the boron toxicity but needs safe handling procedures because it is very corrosive. 

You can also choose to retire that wok and switch to a carbon steel wok, which can hold better seasoning (and also, being many times cheaper, causes less consternation if it stops looking good). For that solution, you also need to season properly, which does have a learning curve at the beginning. 

A side note: 


  Am i doing it wrong 


You may have a somewhat wrong wokking technique - I am surprised that your bottom is so clean while the walls got so much oil polymerisation. My suspicion is that you are overcrowding the bottom and not pushing enough food up the wall. But that is only an aside, since it matters mostly for taste, not for cleaning.