A tracker is not intended to be a representation of the perfect you. Sometimes we can get off track for this reason. The more truthful you are in your tracking, the more power you have to reach your goal. Even if you're afraid of the caloric content or flabbergasted at the amount of fat- write it down. It can be as simple as "Ate 1 piece of Aunt Sue's German Chocolate Cake" or "2 Pieces of candy from the jar at work."
When you acknowledge what you are eating, you will demonstrate more control over time. You will also be more aware of your habits and if you need to tweak anything in the future. Even if I don't know what the nutrition info of something is, I will account for it.