In Part 3 of the Elseworlds Crossover, after Oliver fires an arrow at John Deegan, after Reality is restored we see that Deegan's face has changed since the previous episode where it looks shrivelled and almost like if there is writing on it.
Earlier in the episode, Clark said that using the Book of Destiny comes at a cost, but also it looks like the Book of Destiny is useless since Oliver's arrow hit it and there is a bit of recoil from that.
So I am wondering what happened to John Deegan, was it the result of him actually using the book or from the blowback after Oliver shot it or something else entirely?