I'm getting cold sores more often than usual. what is causing this?

Several things: These symptoms can only be adequately worked up by your doctor. He/she will listen to you, perform an examination, perhaps orders some tests to find out what's wrong.

Altered immunsystems: Repeated close interval cold sores tells me your immune system is compromised. Lack of proper rest, stress, or perhaps something more serious is going on. See your dr. For a diagnostic work up if you feel you are not stressed, have a proper diet, and get enough sleep.