• Not usually. People with recurring cold sores occasionally worry that there’s something wrong with their immune system, or that they’re deficient in a vitamin or mineral. But cold sores are very common, and most people who get them are otherwise perfectly well.
• Sometimes tiredness or another viral illness can make you more prone to cold sore flare ups
• If you’re worried, speak to your doctor- they may recommend some general blood tests to check for an underlying cause.