If i have herpes and my son gets a canker sore does he have herpes how do u know the differance?

Blood test/culture: Both you and your child can take a blood test for herpes and can culture the sore. That should help narrow it down.

Herpes test: A blood test done through your medical doctor is the only way to know for sure.

Have it looked at: A physician or dentist can examine the sore and determine the cause. It may be something else as well, so it's important to have it looked at if it doesn't go away within a week or two.

Different: Lip herpes is different from canker sores. They are caused by different viruses.

Herpes vs Aphthous: Oral herpes is an infection caused by the herpes simplex virus and is contageous and looks more like a blister. Apthous ulcers also known as a canker sore, is a type of mouth ulcer that presents as a painful open sore inside the mouth or upper throat characterized by a break in the mucous membrane. Its cause is unknown, but they are not contagious.

Different: The familiar white "canker" sores inside the mouth that hurt when you drink orange juice are not herpes. Anyone who tells you otherwise is mistaken.