Complex sentence: If the lining has fallen out of the anus and is around 7 cm or less, it should eventually retract back inside naturally, though the retraction can take up to 96 hours (4 days).
Split into simpler sentences: If the lining has fallen out of the anus and is around 7cm or less, it should eventually retract back inside naturally. This can take up to 96 hours (4 days).