A quick trick I use is to think approximately about what I ate. You can measure you actual body weight now as opposed to where it should be. So, say for example you gained a pound over finals week and the days you did log you ate 2000 calories more than you consumed. You can tweak the quantities of the foods you ate until they add up to an additional 1500 calories deficit. I would just wait to weigh yourself several days out from those days if you ate an excessive quantity of food compared to what you typically eat.
If you log nothing on those days the software won't count them towards average daily macro and micronutrient values, if that is what you were worried about however.