If you had a machine that created a window through which you could see the future, and in the future you wrote down the winning lottery numbers and relayed that information to your present self before that lottery number was drawn.
However, in your present selfs excitement, you turn off the machine before your future self wrote the winning lottery numbers into it for your past self.
What would happen?
The disfigured mouse must come from “somewhere”, or rather from sometime.
The logical explanation is: later he has developed his button further, for a longer time jump (and maybe for some other improvement that gave him better confidence) and then he tried it “again”.