You have the right steps taken, now you have to leave the cave after you skin Savior. Hircine should appear again then. You can also keep the cursed ring if you hand it over to a follower after you revert from werewolf.
EDIT: Let me be more clear, with the current patch you need to 1. spare Savior 2. kill hunters 3. talk to savior, agree to leave him. at this point it should be quest complete. 4. skin savior 5. leave cave.
How much mud could a mudcrab crab if a mudcrab could crab mud?
1.Agree to spare Sinding 2.Killed Hunters 3.Talked to Sinding to complete quest 4.Went outside and talked to Hircine to collect the Ring 5.Went back inside and killed and skinned Sinding 6.Hircine appeared and gave me the Savior's Hide
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