Carl was like this when I first got him,What i did was this.I let him bit me on the back of my hand( my hands are very callioused up from working in a hot enviroment and it doesnt draw blood if he bites me there)and as he bite me i went ow ow ow ow ow ow ow until he seen it was hurting me,when he released my hand i went your biteing hurt daddy and pet the top of his head.He continued to bite but each time less and less until now he doesnt bite at all.I dont know if it will work on yours but,It worked on Carl.
Dave