Suggest Cause And Remedy For Pain In The Abdomen

i have a daugher, she is 8yrs now. since 2004 till now she is suffuring from worms..she is scraching at the back. one day i take an assesment, i saw white worm like pins. i give her zentel, but she can t stop from scraching,. i tried vermox, i even take her to the hospital to examine her stools they don t see nothing but i know that my child is sufferin from worms. when she take medicine it only last from 4-6 months it starts again. and thia thia nowa days she is complaining of pain in the abdomen. i am so worried i don t know what to do anymore