It is very common for a fever to cause herpes, and there are more types of herpes, such as when a fever causes herpes of the mouth and lips, which is more common. The herpes virus is normally found around the lips and mouth of a person, but when the body’s resistance is strong, it is less likely to cause an infection, so the herpes does not appear. However, during a fever, the body’s resistance is often weak and dehydrated, so these viruses take advantage of the opportunity to infect the body and cause herpes of the mouth and lips. There are other types of herpes, such as herpes pharyngitis, which is often a viral infection that causes herpes and fever. There are also other diseases that can cause fever with herpes, such as chickenpox and shingles.