[Winkie Expand]

I think she is naive and Dexter has used her as a vessel to speak to the camera/audience.

He's trying to con people into believing he's been through an "amazing transformation" and is using Charlie to have someone/thing to talk to so that cameras pick up it.

PS- I think Charlie is lovely. A beautiful, yet as stated, a naive girl who has latched onto others to justify her placement in the BB house.