da23667a_hews___The_Charmed_Legacy_Wiki__Restoration
[Image] 150px [Episode] 5x12 [Episode Name] Centennial Charmed [Cause Of Power Loss] Cole altered reality to change history just when Paige sneezed and orbed out at that second when the spell took effect. In that timeline, Paige never met her sisters, and only had basic witch powers [Restoration] 
By reuniting the Power of Three in the alternate reality allowed her powers to come back.
Paige Matthews - The Charmed Legacy Wiki
Restoration