Cold sore or canker sore?

My girl friend gets cold sores once or twice a year during the winter which has led us to believe that she has oral herpes. We've been dating and kissing for over a year and I have never gotten a cold sore or shown signs of it. However about a month ago I got a weird canker type sore on the inside of my bottom lip that really hurt. I'm pretty sure I've had canker sores before and this was something different. It was about the size of a small bead and it was white and inflamed. It went away after about 5 days and I haven't had one since. I've heard many different opinions on whether you can get cold sores inside your mouth. Could this have been a cold sore? I would like to find out before considering oral sex with my girlfriend because I would not like her to get genital herpes.

There is no way to determine the cause of this sore given a verbal description, especially now that it has been healed and gone for several weeks. Usually cold sores are outside of the mouth, but this is not a firm rule.

If you go to your doctor he can give you a blood test to determine whether or not you have been infected with HSV-1 or HSV-2, the viruses that cause cold sores and genital herpes.

Many people are infected with one or both of the HSV viruses and never know it. It is possible to carry the virus without ever showing symptoms.

It will be possible for you to transmit HSV to her during oral sex if you have been infected with the virus. Unfortunately, even if you test negative today, that's no indication that you will test negative again a month or a year from now.

The only way to engage in oral sex and minimize the chance of transmission is to use a latex barrier of some kind. An easy way of doing this is to unroll a condom and use scissors to cut along its side to form a rectangular sheet of latex.

cold sores do not manifest inside the mouth, what you describe is caused by poor oral hygiene and too much acid in your food. As she obviously does have herpes simplex, do not accept oral sex from her, as she can be shedding the virus for up to a week BEFORE a cold sore shows up, in other words you can never know when she is infectious.

It sounds like a canker sore. You are a responsible person. Thank you. A simple blood test can tell if you have oral or genital herpes virus.
I am surprised that Nurse Betty? would say that canker sores are caused by poor hygiene. Doctors do not now what causes canker sores. They do know that they run in families, and think that stress ,allergies and some other factors may cause these.Nothing is mentioned about poor oral hygiene. Familydoctor.org. Enter canker sores in the search box

you need to talk to your doctor cause your girlfriend can have herpes and it lays dormant in your body until some kind of sickness, her period, stress. does she have bumps on her private area thats want i wuld worry about herpes has no cure thats for life and what ever she has down there you can get in your mouth be safer good luck