Josh is right. Just peel or draw knife the bark off of hickory, and scrape off the brown criss-crossing layer covering the first layer of white wood. That very first layer of white wood underneath is your back, and you shouldn't have to cut through any knots. However, if you have already cut down into a layer or more and have to do something with the knots, I'd just leave them a little extra wood on top, but nothing really special. Hickory is very resistant to breaking, and I have violated all kinds of knots before and never had a hickory break on me. Where is the knot located on the bow?
~~Papa Matt