Miners sold the Red Kryptonite that was inside the rings to Smallville High to sell to the students. Clark bought one using money he earned doing farm chores. Pete and Chloe also bought their own rings. After the death of his baby brother, Clark took the ring from the desk drawer in the Torch and put it on, to mask the pain, transforming him into Kal. He lived the high life in Metropolis, where he partook in anti-hero actives until Jonathan made him destroy the ring.
Red Kryptonite ring on Hybrid Kryptonian, possibly Excelsior class ring
It's unknown why the Red Kryptonite rings didn't affect Pete and Chloe, seeing as Red Kryptonite lipstick had an affect on Lois, but it could be possible that Red Kryptonite work differently for humans and needs to get into their bloodstreem to have an effect.
Clark's Red Kryptonite ring only appeared in Red, in Exodus, Exile and Phoenix, he wore Chloe's Red Kryptonite ring.
