Recrudescence (noun)

1. The resurgence or reappearance of something after a period of inactivity or decline.
2. The return of an illness or disease in a more severe form after a period of improvement or remission.

Origin:

From latin recrudescēre, meaning "to grow raw or become raw again".

Examples:

1. The recrudescence of the virus was a concern for health officials who had thought it was under control.
2. The recrudescence of the old-fashioned style of clothing was a surprise trend in the fashion world.
3. The recrudescence of the traditional dance was a welcome revival for fans of the art form.
4. The recrudescence of the company's profits was a result of new leadership and innovative strategies.
5. The recrudescence of the conflict between the two nations was a cause for concern among peacekeepers.