K.R.
Dear Mommy of One,
You are not the only one with a biter! Lots of children bite for many reasons.
Do you have "chew toys"? Just like every living thing with teeth, children need to breakin thier teeth. Having a "good place" to bite is necessary...we bite our food and "this thing". What this thing is differs according to culture and life...a rope, a specific toy, a stuffed elephant with a nose, a mesh bagt with crushed ice inside. One of my friends has a dog chew toy for her daughter specifically for the reason that if she wants to bite someone find the bone!
You re brave for stepping up and wanting to deal with it. when you say no, don't smile or smirk. Lower your tone so your precious child knows that you are serious. Usually, at 21 months, children want to please thier parents.
Another idea might be to try teething biscuits and/ or vegetables that crunch...celery, carrots, some LLL might recommend dog bones or even wood. Keep your pediatrician up to date.
Hugs to you! Keep yourself focused on all that you are doing right!
With hope and joy,
K.