How did ben 10 lose ghost freak on his omnitrix and witch episode he?

Ben 10 didn't lose Ghostfreak in the episode "Witch" (and he didn't actually lose him in any of the episodes in the original Ben 10 series). He was actually *stuck* as Ghostfreak for several episodes in the original Ben 10 series, starting with the episode "Ghostfreak."

Here's what happened:

* "Ghostfreak" episode: Ben accidentally fused with the alien Ghostfreak, a Ectonurite. This resulted in Ghostfreak taking control of Ben's body.

* "Ghostfreak" and subsequent episodes: For a period of time, Ben was unable to revert back to human form, and he had to navigate the world as Ghostfreak. He was essentially "possessed" by the alien.

* "Ben 10,000" episode: Ben 10,000 from the future traveled back in time and helped Ben remove Ghostfreak from his body.

Therefore, Ben didn't "lose" Ghostfreak. He was freed from Ghostfreak's control.

It's important to note that the "Witch" episode focuses on Hex, a villain who uses magic, and doesn't have any connection to Ben's Ghostfreak experience.