Discuss with doctor. If itching persists a second treatment may be necessary and topical or oral steroids may be necessary to treat the symptoms.
Probably not. If one is properly treated with an appropriate scabicide and proper hygiene was performed, there is generally no need to retreat the scabies. Itching from scabies often occurs long after the scabies mite has already been eliminated. This is because we are often sensitive to the fecal matter from the scabies mite, and not just the mite itself. This can take another 4 weeks to resolve completely.