Neal knew something weird was going on. A few days before, his lip started tingling and felt a little numb. He didn’t pay much attention to it then, but now there was a certain throbbing something on his lip and it wasn’t pretty. At first Neal thought it was a zit because it was red and tender, but then it blistered and opened up. Neal had a cold sore.
Maybe you’ve heard of a fever blister — a cold sore is the same thing. They’re pretty common and lots of people get them. So what exactly are cold sores and what causes them?