Please be cautious! If I were you I would bar access to high value items now and find a trainer once again to help you through this. If you do this yourself after the dog has had a bite already I would be concerned he would go for you too. Also do a search on these forums for NILIF. You have a lot of work ahead of you..
Is your son's hand OK? Puncture bites can be very nasty and tend to get infected. Only asking cause you did not mention if he got it checked out.
(I would not recommend treating at home)