strange bump under tori

so i have 'tori', and it is normal for me. however recently i noticed on the underside of them that there is a small hard and painless bump that i can feel with my tongue. my dentist doesn't think it is anything to worry about, but i'm really concerned about it b/c there is a beginning of another bump that wasn't there before. i recently became sexually active, so i am wondering if it could be a case of oral HPV-- but my tongues, gums and lips are fine. what does it sound like to you?