It’s explained next chapter. He gets back his memories because after an undated death a person is granted wishes. He made a wish to remember.
Carcel probably regained his memory ultimately because the Apostle granted him memories just like the apostle just gave Ines new memories in ch 95 & 96. The Apostle is trying to help Ines survive and finally live out her life to break the cycle of repeated lives.

**Spoiler**??
So Emiliano also remembers his past life? Go Cárcel, Ines and Emiliano know what happened before??? I’m so confused!!!