After the Naruto-Sasuke showdown and they blew their arms up, why didn't Sasuke get his arm repaired like Naruto had? Well, even with the bandages and all. I don't really know what's within the bandages.
He basically said he needed time to atone for his sins and that is why he went off on his own. It is almost like he is telling himself that he deserved that. Inside Naruto's bandages are cells from Hashirama that are meant to regenerate his arm. I am assuming in the future when it is fully finished, the bandages will probably come off. It is also possible Sasuke will take the same treatment some day.
After there legendary fight, which ripped off their arms. Lady tsunade treated naruto by recreating his arms using hashimara cells.
When she tried to help sasuke he refused -
first, he can create susanoo so for fight or living, he doesn't need to treat his arm.
He wants to have a reminder of what he has done and should not become something that can harm his friends or village.