Cold sores can be detected through various symptoms. One common symptom is, you feel difficulty in eating, because when food comes into contact with a cold sore inside the mouth, pain shoots up. Salty foods have a special way of making the pain almost unbearable. Another symptom is a swelling on your lips. It can sometimes create fevers, sore throats, and various swells in different parts of your body. Cold sores may be termed as fever blisters and are caused by the herpes simplex virus. Although this is considered a minor ailment, it can really be extremely irritating to the victim. If the person doesn’t eat because of it, chances are, he or she will feel very weak after a time. In short, it is important to get rid of cold sores as soon as possible.