I have a canker sore and i perform oral sex on a woman, can i give her genital herpes?

Oral ulcers: Canker sores are of unknown etiology. Without seeing what you have, herpes simplex usually presents on the external surface of the oral cavity, predominantly the lips. Canker sores are often in the mouth on the mucous membranes or gingival surfaces. If truly canker sores they will not transmit herpes because that is not the cause.

Yes: If you have an open sore on your lips, tongue or in your mouth and you have sexual contact the virus causing the lesion can be transferred to your partner.