Hellbound: Hellraiser II

We see the origin of Pinhead as a British military officer, Elliott Spencer, who uses the Lament Configuration, the doorway to the world of the Cenobites, and becomes a Cenobite.

Kirsty Cotton has been admitted to a psychiatric hospital, still haunted by visions of the unspeakable horror that destroyed her family. Interviewed by Doctor Channard, and his assistant, Kyle MacRae, she tells her account of the events depicted in the first film, and pleads with them to destroy the bloody mattress her murderous stepmother, Julia Cotton, died upon. Despite her frantic urging, MacRae is the only one who seems to believe her. Read more on Wikipedia.