@Mori
Considering it’s bandaged, I’d say yes. Bandaging is to prevent bleeding but also to prevent infection/hold something together. The idea of it bleeding would mean it’s got a steady supply of bloodflow and probably will regrow/heal over time. As I said, look at his scalp; it’s shaved around the base of the horn, meaning they needed the area sterile.
Looks like they shave the area and then bandage it. Considering it’s such an important “organ” to a unicorn, it might be able to regrow, but it’d make life for the unicorn a bit more difficult, much like a pegasus who can’t fly..