What Does A Bump In Vagina Indicate?

i am a 20 year old female who had a c section in january and had mirena inserted in april. ive tried and tried to reach the strings but i can't. there's this large bump, really large, and i can't reach behind it if that's where the strings are. my doctor said they were at 6 o'clock but they're not there. i haven't had sex since i was 8 months pregnant and have no one to help me check. can you tell me what that bump is?