Is the Obliviate Spell Permanent?

In the movies, Hermione cast the spell “Obliviate” on her parents, making them forget they ever had a daughter. Since they were muggles, she wanted to keep them safe from Voldemort's influence. “Obliviate” is permanent, so the tragedy is horrific.

Can the Obliviate spell be reversed?

In the books it's said to be impossible to undo Obliviate without destroying their mind and killing them. Voldemort did it to Bertha Jorkins. Everyone here answered the Hermione question. But yes, memory charms can be broken.

Can Hermione undo the Obliviate spell?

Lockhart's memory loss is permanent, but the Memory Charm doesn't necessarily have to be. After Voldemort's death, Hermione is able to lift the spell on her parents.