One of mine went thru about a 3 month phase of that around 18ish months. He lived in a long sleeve swim top for a lot of the time 😂 that way it was just tight enough that he couldn’t pull it up and then he stopped breaking the skin because of the shirt. It could also be from frustration if they’re having trouble conveying what they want. We did weening off things with vinegar as well. He would bite, I’d put a little vinegar or apple cider vinegar on my finger and rub it next to where he bit. Made sure to not go on in case he broke the skin. The smell helps but the taste works too. A couple times worked well for mine! (It sometimes can cause skin irritation so use with the knowledge of your kids skin sensitivity!)
He could be expressing frustration. I would just interrupt the biting with distraction. Maybe explain to him that you love him and it’s your job to protect him so you can’t allow him to bite himself? 🤷🏼♀️