End grain tear out is the result of two factors, 1- tools not sharp enough and 2- the angle you are holding the tool to the wood. There is a bevel on the front edge of your tool. The tool should be almost directly be the same angle as that bevel. Ideally, a tool should "slice" wood, not tear it. If you just hold your tool straight up and down and approach the wood at a 90 degree angle, that is where you will experience the most end grain tear out. If I explained myself well enough, you may not even need sandpaper. And if you do, you can start at a much higher grit