Artemis Fowl y su peor enemigo (Artemis Fowl: The Time Paradox) Book

You do not own a copy of the rule book, and if you do, you have certainly never opened it.
I liked this book more than the last one. But still this book has little problem which I faced.

In this book, Artemis' mother gets ill by some serious disease. There is only one cure which is an extinct species. He asks Fairies for help. With the help of fairies, Artemis gets back in time to find that species. But he comes to know that, in past time, his younger self and Opal Koboi (antagonist), are also after this species.
The whole book revolves around how he will get that species to present time through life threatening dangers.

Main problem is:
This thing didn't look good to me that, that species got extinct by Artemis himself when he was younger.
This series always set Artemis for every bad deed. I liked that thing in previous books. But in this book, this thing seems little baseless to me.

Never mind, I enjoyed it a lot!
2 books are left!! Hope I will get the good conclusion!
(^_^)