Board Thread:Naruto Discussions/@comment-27863200-20160302112610/@comment-734582-20160302224439

Tengen Toppa Ita-Sasuke wrote: Does Gyuki really respect A that much? I thought that it used to go on rampages. Am I wrong? Of course it goes on rampages, it wants to be free. But a human taking on a Biju 1v1 and not dying instantly? Only a few people have managed that.

As Biju are gigantic masses of chakra and can partially transform that chakra, i think it's fairly obvious that Gyuki can simply chose not to regenerate that horn. I'm pretty sure he regenerated all his tentacles even after them being ripped off repeatedly. It would be weird if he can't regenerate his horn all of a sudden.