What should I do, as I asked my sister to take out an interest-bearing loan, and I used the money to build a house, and my sister is the one paying off the loan?

It is forbidden to borrow from an interest-based (usurious) bank with interest. Borrowers must make sincere repentance and not return to it, because the Prophet, peace and blessings be upon him, "cursed the one who consumes usury, the one who pays it, and its two witnesses, and he said: they are all equal in sin." Dealing with an interest-based bank is cooperation in sin and aggression, which is prohibited by the Almighty's saying: (And do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty). One should increase seeking forgiveness and performing righteous deeds.