Is this a cold sore or just a small zit?

This morning I woke up and was getting ready, when I was brushing my teeth and went to pat off my mouth, the area of my bottom lip line was a little sore, like pimple coming in sore. I looked up close, and it was just a small zit looking thing that had a white head on it. I was afraid to pop it because I didn't want it to look red and disgusting, so I just let it go. It is very, very small, whitehead, just some pain when I press on it, that's it. I have had an STD test telling me that everything was negative except I tested positive for HSV-1 (cold sores), although I have never had one before. Does this sound like a cold sore?