Actually they are different. Demonic possession is when a demon is actually inside a human and either indirectly/covertly or directly controlling the host. But demonic influence can happen, even when the demon cannot gain entrance into the body of the human. It is the lesser of two human/demon forms of interaction.Demonic possession, demonic influence, seems to me to be semantics. Still, your choices are YOURS to make, whether good or bad.
As far as my theology being wrong, I say who are you to make that statement? From your posts, you aren't exactly Billy Graham.
The scary thing is when a person lets go of their personal power, wallows in sin/drugs/alcohol, and becomes vulnerable to possession. But I do realize some possessed people have good hearts and yet seem singled out by demons, for some reason, to be tortured and possessed, if possible. I've watched a few fascinating but disturbing interviews with exorcists.