Hey there, don't panic yet. What symptoms do you have?? Just use condoms with the new guy if you do become sexual and you don't need to tell him anything! Is there any chance you had the vaccine for genital warts. Most kids get that around age 12 or 13. My sons did. Do you remember getting any vaccines then? But explain what you see or what you feel and we'll try to help.
At 15, it's not unreasonable for you to see your doctor by yourself? Like your mom waits outside? Not sure how that will fly though so there is the other option that if you live in the United States, you could get to Planned Parenthood which will be able to examine you and not involve your parents. Are you in the US?
Understood. Are the spots raised? Are you sure they are new?
So, your mom probably has a vaccine record for you? Can you ask to see it? Check the file? That would be helpful. But if you can't get to the doctor yourself and/or can't be seen by the doctor without your mom there, you'll need to tell her. Warts are contagious but don't hurt. So, you really need to determine if this is what is going on. I am guessing your mom doesn't know you are sexually active? Do you have a sister (older), aunt or older cousin that you could confide in?