My new 7 week puppy is craaaazy biting!!

[Blue Tango]

My new 7 week old puppy is biting and nipping and is actually getting quite aggressive with it and it is hurting. I know that he has not developed bit inhibition yet so we have been trying to teach him. We have tried the yelping and ignoring, we have tried the gentle no. We have tried coddling and hugging him with pressure. He does not chew anything else but us and of course his toys that I quickly substitute when he has these attacks which can last 1-2 hours or all day. It is exhausting! I have also tried the looking away part and he does fall asleep easily when I do this and rub his belly but honestly, we have tried telling him no. Nothing seems to be working. I even have bought the pheromone lavender spray. It is getting frustrating. I have just joined this forum and I will try the yelping and ignoring again but he has been with us 1 week. The first few days of nipping, didn't hurt and we understood he was teething and the owner told me to hole his upper jaw back slightly. But now there is actual biting with his little sharp teeth and I and my husband have scrapes all over. It is no longer enjoyable. We can't even sit on the sofa without him trying to nip..and bite. Overall with other things he is wonderful but I don't get it. I am trying not to be afraid of it and maybe it is my fault for putting my fingers in his mouth as I was told to let him bite a little to teach him to understand bite inhibition but now I fear it has backfired. It is causing great stress for us. I am reading Pippa Mattinson's The Happy Puppy Handbook and really I am out of ideas.