He can't hurt you in real life but its strange that you see him when you blink. Maybe its cause your thinking too much about it and it scares you. Sometimes people who have anxiety hallucinate. Try to not think about it so much and if you need to talk about it with someone in your family talk to them. Do something you like to do that helps forget about it too. If it continues to bother you try finding a psychologist. You could talk to them and get advice from them if it ends up bothering you to the point that you can't sleep or concentrate on school or other important things. If I had a enemy in my dream I couldn't fight I would call a dream character or my dream guide to fight it. Like if he pops up you can try calling Naruto and watch him kick his butt. You could even join in. If naruto doesn't appear turn the guy into your friend.( > w > )/ Sometimes they might not like that but be brave. They can't hurt you in real life.