I have HSV-2. For 3 days now I've experienced lip twitching every few minutes. No cold sore outbreak yet. Lip twitching due to herpes or something else?

Not herpes. Herpes doesn't cause lip twitching. And unless you caught oral herpes at the same time you acquired your genital HSV2 infection, it is unlikely you have oral HSV2. Most "twitching" of small muscles (in the lip or anywhere else) is called benign fasciculation. It's harmless and usually doesn't indicate any important health problem. Google "benign fasciculation" for more information.