If you truly cut through the CC to the base the only perfect fix is wet sand the remaining clear and lay on more.
Uncovered BC will look ok for a while after you buff it out. In a short time it will look like more buffing is needed. You can buff it over and over til you cut the BC too thin. Then you start all over with new bc and cc.
I've just started to spray bc/cc but from a lot of reading on it, you should wet sand, spray some base to blend/cover, then clear the entire panel. A lot of info can be found at the following site. Hotrodders board