Well I had my first oral sex when I was 13 and we did not use a condom. I went to the doctor and he said I don't have any diseases or anything. Then I had my second oral sex when I was 16 now. I just went to the doctor and he said that I don't have any disease or anything again. I started to get cold sores around my mouth, and it's November, and I'm wondering if this has anything to do with the oral sex I had 2 weeks ago? Maybe it's just the weather or herpes?
A good place to start is knowing what, exactly, herpes is. Read more about herpes here. Now that you know a little more about herpes, consider how often you have sex. Are you having vaginal intercourse as well as oral sex? How many partners? Do you know the sexual history of your partners? The point isn't to scare you into thinking everyone is a disease farm on two legs, but this should reinforce safe sex practices so you don't have to worry about herpes.
Your concern about herpes is real, but risk of infection through oral sex is not as high as you might think. In order for you to have herpes from oral sex, your partner must have the virus on his/her genitalia. So if you were doing more than oral sex, you might also have genital herpes. Your doctor already confirmed that you don't have herpes, so chances are you have good old-fashioned cold sores.
This part is very important, so pay close attention: when you have an outbreak on your mouth, do not kiss or engage in oral sex as you could transmit herpes to your partner. If you want to promote your body's defense against cold sores, take lysine when you have an outbreak. You can buy lysine in the vitamin section of most grocery stores, it's an amino acid that helps your body's immunity system.