I believe she will recover it when she' s 10. Wearing diapper at night is ok as long as don't let other people know it since it might be hurt her self-esteem.
See the below words:
Bedwetting runs strongly in families. More than 5 million children in the U.S. wet the bed.
About 9% of boys and 6% of girls still wet the bed at age 7. The numbers drop slightly by age 10. Although the problem goes away over time, many children and even a small number of adults continue to have bedwetting episodes.