Herpes Doctor

About 40 minutes ago, it felt like I had lightly cut my upper lip. Suddenly, the left side of my upper lip started to swell and is now twice the size of the right side. I took an antihistamine about 30 minutes ago, but it hasn't helped, ruling out an allergic reaction. I've read up on symptoms, but still am not sure. Do cold sores usually start off as significant swelling? I don't believe I've ever had one before, so I thought I could find some help on here. Thanks :)

ETA: I did look at the site's Oral Herpes Symptoms FAQ, but am still a bit confused.

***Okay guys, the swelling went down completely and there are no signs of a cold sore now, so I guess it was a false alarm. Thanks :)