My 8 year old is possessed! PLEASE HELP!!!

I have two children, I homeschool both of them. It's hard getting them to socialize with other children so I let them go to friends houses to play sometimes. I let my son go to a friends house, I don't know them well but I thought the mother was a Christian. I was wrong. When my son got back home he told me that they watched Harry Potter!

I immediately took my son into his room and made him start praying but I think it was too late already. I was reading scripture to him, trying to get him to understand how witchcraft is evil and he just started yelling at me and telling me to stop! It's like the words of the scripture were hurting him. This was the first indication I had that he was possessed.

Ever since then he has been acting differently. He doesn't do as I say, he yells and throws things. It's gotten so bad that we've had to cut back on his schooling. It's been getting so bad that I've had to keep him locked in his room for long periods of time.

The other day I caught him telling his sister that the Bible is "stupid". I told him not to ever blaspheme and asked him why he would say that. He told me that the devil told him to say it!

I took him to our church and the pastor sat with him a while. After running a few tests he told me that my child is definitely possessed. He said I should keep my son away from my daughter because the demon might travel.

I've tried everything and nothing is making the situation any better. I've had people from my church come and we've prayed over him. I read scripture to him and make him pray. The last time we had church members over he refused to stay still and I had to hold him down in his bed while we prayed.

I m so worried, what should I do? Does anyone else have experience in this sort of thing??

My pastor said I should put him on a restrictive diet to help drive the demon out. Will this help? I've started feeding him mostly rice and water but he seems to be getting worse.

Please help!!