My Bichon Frise shows aggression to children. I am taking him to obedience classes at Pet Smart. This is not helping. What can I do?

I know you probably don't hear a lot about these dogs, but here goes:



I purchased him from a private breeder (mother very sweet, siblings all looked fine-clean home, etc - husband and wife stays home with dogs. We brought him home and everything was fine. He would play bite was the only major thing I noticed in like the first month. About a month after we got him, some relatives came to stay for 6 weeks temporarily with us. They have 2 children, ages 2 and a half and 6. Both of the children were afraid of Bailey and used to scream away from him. They by no means ever hurt the dog. My son is 4 years old. I admit that he occasionally would pull dog's tail, play rough, etc. I am presently working with him on this. My worry started when my son bent down next to dog with his face near dogs behind. Bailey turned around and bit him over eye, leaving like a bite mark that luckily went away in a few days. This is when the worry began. It seems like every time my son goes go even pet Bailey he growls and nips at him. I keep them on CONSTANT supervision at all times. We are currently in obedience classes at Pet Smart, and Bailey is learning a lot. I admit that he is very intelligent, and his breed is not known for being temperamental. A visit to the groomer almost had me in tears. She told me that Bailey was worse than before, and that someday I might have to put him to sleep!!! She upset me so much I don't think I'll go back. Bailey was also just neutered, along with having hot spot shaven. He had to stay at pet hospital for 2 days, and he was very irritable for about 4 days. He is better now. He has licked hair off one paw that they put anesthetic in. The vet says this is obsessive/compulsive thing. (is this genetic?). By breeder has told me that I can bring Bailey back if it doesn't work out and she will give me $ back, which I think is nice. I even called then to express my concerns. He told me that none of their other pups ever had aggression problems, and breed is not known for this. I am trying to decide whether or not to take Bailey back. I spent $600 on him, and I want a puppy with good temperament. If we caused this, then so be it, but if not, then I want what I paid for if you know what I mean.



My main question here is do you think Bailey's problems were inherited by his parents, or did environmental factors cause this? I am meeting with animal behaviorist on Thursday, and she will evaluate Bailey with my son. Also, if we train Bailey to behave, will he stay like that, or will he revert back at some point? Help me, I need to make this decision. Thanks!