We went through this recently..Ours is now 4.5 months old..
We have found that you always need a toy or bone near by..
They need to be chewing.
Also learned that they MUST go to Puppy Training class.
When ours nip,we say LEAVE IT in a deep serious voice.
When he stops biting you give him a treat.You must do it ALL the time..
Their teeth are like razor blades..
Also learned he must be walked often & he gets to go to the dog park every other day..Its exhausting..But they need to be exhausted!
Make sure to have that toy or bone near by to put in his mouth rather than your arm..
They think your their litter mate..
We can see a difference in him now that he’s approaching 5 months old..
We are also starting him in Obedience School..
He is going to be HUGE..He must be trained now or it will hell come winter..
Hope this helps..