You can get things like that in your mouth for a lot of reasons. That said, in your shoes I would go see a doctor. The problem would not be caused by the birth control (if you are talking about the pill) but who knows if it is an STD or something totally else; for example, one time I got gum boils from lack of vitamins. See the doc, get swabbed, and find out if it's a cold virus, or an STD, or strep, or the flu, or what.
Hi there. So, you are entering a new phase of your life and it is natural to be a little anxious. The pill does affect our hormone levels and this in turn can have different effects on the body. Oral contraceptives can indeed impact your mouth and oral health. Here's an article that talks about it https://www.webmd.com/oral-health/hormones-oral-health#1 There is a lot of information on this topic and this is just one resource. Your mouth issues could indeed be a result of taking birth control pills. You have to take really good care of your teeth and up your oral hygiene. I think the benefit of being on the pill may outweigh the downside if you are becoming sexually active in terms of having vaginal intercourse. Unplanned pregnancy can derail your life! So, you probably should see the dentist and make sure your mouth has no issues that the hormonal changes are exasperating.
With regards to oral sex and std's, that 'can' happen. Giving oral sex puts you at risk for gonorrhea of the back of your throat and possibly herpes but that is less common to get genital hsv 2 orally. But it's wise to use a barrier of some sort during oral sex and condoms during intercourse to protect yourself from std's.
I'd give the doctor a call that prescribed the birth control and discuss these things. Let us know how you are doing and what you think!
Do ask your doctor about your birth control being involved for the issues of your mouth. I suspect they are indeed related.