What could this possibly be?

okay so, i have 3 cold sores on my lip i have 2 on the uper and 1 on the lower. They are really small and kind of have white in the middle. Could it be due to stress: I had my 1st heartbreak & midterms are this comming week. I was sick also last week. Could any of this cause 3 little cold sores?! help haha also who should I put on them to make them go away?