Talk to Pediatrician on Pinworms In Vagina

My daughter is facing this issue when she was just 1 year old. In a few months she starts crying in the middle of the night and touch between her legs with pain and I checked that place I found a pin worm moving outside her vagina I removed it from there and then she will sleep. We discussed with doctors several times they suggested some medication and they worked for few months but then again it happened and time to time she have to face this situation with the gap of some months but this time it’s almost a year and half she was restless last night and when I checked there was tha same pin worm moving. We are very concerned about her problem she also smells bad between her legs. Why is this happening to her is there a permanent solution for this? Now my youngest daughter who is just two years old is also showing same attributes as itching between her legs and smells bad Please guide and share the knowledge I’m attaching the photos of that worm