Thom Browne Button cheapest Down Shirt

Product Name: Thom Browne Button cheapest Down Shirt
Please message if you need measurements! ×Thom Browne Button Down Shirt (Size 0) It is a very slim fit. PLEASE READ!: I bought this on Mercari so I am not sure about the authenticity but according to the originally seller I got it from they said it was authentic and they got it from the NYC store. I haven't worn this once since I got it but it's a super cute button down I just had nowhere to wear it too. Problems: -The button on top is slightly getting loose when I was looking at it so be cheapest careful! -One of the reasons I don't believe it is authentic is because the 2nd to last button is missing a button (Picture shown at the end) -There is also a slight stain (Picture shown at the end).