My dermatologist removed a clarks nevi (?) from my chest. She left a border. Should that be removed now, or should I wait 2 see if there are changes?

Resect and screen. I would remove the whole lesion with clear margins to be safe as there was something concerning about it which warranted the resection in the first place. It is possible that another area of the lesion has cells which have the potential to develop into a tumor. If you have many moles it is important that you also make sure and follow up regularly with a dermatologist for screening.
Atypical. If there are any atypical or "dysplastic" cells remaining the nevus should be removed.