Well first off, he is too young to be aware from his mother. A puppy needs to stay with his mother and litter until at least 8 weeks, longer for small breeds. Until 8+ weeks he does not have the socialization skills that he needs. Those skills and time is crucial.
You need to redirect him to chew toys. It's important that you teach him what he CAN bite and chew.
https://www.youtube.com/watch?v=ZKjk84OkzcI
You need to redirect him to chew toys. It's important that you teach him what he CAN bite and chew.
https://www.youtube.com/watch?v=ZKjk84OkzcI