Please help!

So last night I was going to the bathroom when I noticed it was both painful to urinate and wipe. At the moment I thought nothing of it. This morning I woke up to that same pain when I used the bathroom. I got curious and started looking to see what might be making it so painful and I noticed I have bumps around the opening of my vagina. One of them is about the size of an eraser and white and the others are smaller and red/purple. I started searching the web just to freak myself out even more. Everything I read said that it was an STI of some sort. The problem with that is im only 16 and I'm still a virgin so there's not way it could be and STI. I've never had oral either. Please help! I'm freaking out and don't know what to do. I don't want to tell my mom just yet but it's painful. I had no problems at all up till last night.