My 5 years old girl has avery hard small stool

Patient: My 5 years old girl has avery hard small stool for awhile now with astrange skin like membrane with it twice one time from 3 days the skin was big and today asmall one .from 2 weeks sshe was screaming from an abdominal pain we took her to a doctor saying it was UTI she did a urine sample ofcourse and CBC and it was good with Hb. 12 .im so scared from that skin coming out of her would you please guide me where to go

Doctor: