I'm not going to bash you but just have to say that you have created quite the problem with your prior training techniques. My suggestion would be to go to the top of the training forum and read the Sticky called How to Train a puppy mill rescue. There are a lot of really good ideas that you can use to help overcome the trust issues that your little guy is having. Everything must be positive reinforcement for him ever to be able to trust again but it is possible with a LOT OF WORK on your part. I would also suggest that you purchase bellybands if he is still having accidents in the house they will help a lot too. Just remember treat, praise and never left your hand to your little guy every again.
Dogs are very forgiving and only show total love and devotion to their owners.