Why do we pick at ourselves? The atonement is amazing. When we fall and sin it is there for us to heal. If we repent and change our behavior we form a type of scab and start the healing process. But may of us pick at our scabs and prolong the healing time. Others pick at faint scars that are left from years earlier. Scars that the Lord can't see anymore but we let ourselves see them still. The hardest part of repentance is the picking of scars and scabs...forgiving ourselves.
As explained to Simba in The Lion King, the past can hurt - but you either learn from it or let to control you. uh or something like that