Last night I saw a small white head pimple on my lip, and thinking nothing of it, I popped it. It turned a little red but I figured because my lip was so sensitive. I woke up the next day and it was a little swollen and was told it was a cold sore, but it doesn't show or have any symptoms of a cold sore such as the burning or itching feeling. Is this a cold sore or just an irritated pimple?