Hi dear.... yes biting can be a sign of teething. Most of the babies have itching gums and they feel like biting. Along with this they may have irritation and feel uneasy due to the pain in gums. So, they try to put their hand and fingers in mouth for soothing pain. Because of putting hand in mouth always germs enter into their mouth and pass into stomach and cause motions. Some kids reject food due to this pain. Some may have fever also. So, don't get tensed. Clean your hand and slowly massage your kid's gums. This soothes their pain and make them feel comfortable. Take care dear