If it is due to a fluid collection (seroma) or blood clot (hematoma), then it may persist for 6 to 8 weeks, and, rarely, even longer. If it is due to an early recurrence of your hernia, then it will never go away by itself.
Sincerely,
Robert A. Wascher, MD, FACS
www.doctorwascher.com
Author, "A Cancer Prevention Guide for the Human Race" (2010)