The spot below the bottom lip just above the chin is a problem for me too. If I don't sufficiently stretch that area and use a scooping stroke I tend to nick it as well. As far r the the cut on the cheek I assume since its you left side you may be usuing your off hand. I find a confident stroke to be the fix if you are being tentative you tend to start and stop . Stopping I the middle of a stroke while the edge is still in contact with your skin is a sure fire way to nick ones self. We have all had the same problems and set backs, just stay at it.