Cold sores usually do not require medical care. A few people may have cold sores that come so frequently that a doctor will prescribe a daily medication to reduce the number of attacks.
The very first time someone gets a cold sore (known as the "primary" attack), the symptoms can be severe. In some people, the first attack of herpes is associated with fever, swollen glands, bleeding gums, and many painful sore(s) around the mouth (gingivostomatitis). These signs and symptoms may last several days. The sores heal completely in two to six weeks, usually without scarring. Virus can be recovered from the saliva for days after the lesions heal. Because many people acquire the virus early in life, primary herpes usually happens during childhood. If the attack is severe, a doctor should be contacted. The doctor may prescribe medications that can shorten the attack. Difficulty in eating and drinking may lead to dehydration, which may also require medical attention.
People who have very weak immune systems from chemotherapy or other causes may have very severe outbreaks of cold sores. These look like the primary attacks described above. Medical care should be sought promptly to avoid complications.
Rarely, herpes simplex may infect the brain. People with this condition usually have fever and confusion. This infection requires hospitalization and intravenous antiviral medications.
In a few people, cold sores treatment will be associated with painful skin lumps on the front of the legs known as "erythema nodosum." Erythema nodosum can be self-limited and usually goes away on its own in three to six weeks. If this happens, the person should be seen by a doctor to find out if prescription medications might make the condition go away faster.
Sources www.emedicinehealth.com