Felt something weird inside

Hey all, 4 weeks ago i got my mirena iud inserted. Since then ive been trying to check the strings a lot but my cervix is high so i could find them only a couple times. However, a few days ago, i noticed a kind of crusty spot in my vaginal wall. Like when i go with my finger over it, it feels like a crust. Deffo not an iud string because those are way higher. Im not sure if what i feel was there before. Is this something to get checked for? I know vaginal walls can feel not completely smooth and i’m quite a hypochondriac so i’ve called my clinic quite a few times about things. Is this something i need to call for? I don’t have unusual discharge, no itching and no other symptoms