I've spent a long time playing Terraria and I'm about to defeat Duke Fishron, but a new update came to my kindle fire HD tablet on July-15-16 and when I tried to log into my main world, it would load and then crash the game. But it lets me on my other less sophisticated non-main worlds.
I'm sorry, there is no way you can recover it. My friends who played terraria reported that after the update, they are not able to recover. Try contacting their support team.