How should I take Valacyclovir exactly? I read the instructions but they are confuse.

First it says that adults should take 500mg every 12 hours for simple herpes infections. But right below that, it says that to treat herpes on the lips, you should take 2000mg every 12 hours instead. Which one is right? I don't have any blisters now but I woke up with some pain in my lower lip. It could be just a pimple but I don't want to risk it so I wanted to start the treatment as soon as possible.