I have advice as a psychologist and a patient who has had skin cancer. You are already doing the right thing by going for your exam. Remind yourself that you're doing the best thing for your health by having the exam. The day before, or the days before if you're anxious then, my advice is to try to do an activity that helps you relax. For me, that meant going walking with a friend and taking an exercise class. I also did some yoga. But I recommend doing whatever relaxes you. I also recommend trying to distract yourself from the exam. I think distraction is a great coping mechanism when you are already taking action, in other words, when it doesn't keep you from doing what is necessary to protect yourself (i.e., having an exam). So do whatever it takes to distract yourself.