Will my large seroma go away? I'm 9 days post mommy makeover.

The fluid and general area can feel firm or hard as your body builds a scar capsule around it.  You might speed the recovery process with a tight compression garment or spanx.  This can be frustrating after a big surgery like this and it may get firmer before it gets better.  Massage of the area sometimes helps the squeeze out that fluid and break down scar.  Eventually your body will smooth it out as the scar inside softens over time.  Good luck, Dr. Aitken

Dear imchanellove,seromas do occur often after a tummy tuck. Smaller seroma can resolve by itselves but larger ones require a drainage. Based on your description, 400cc is a big volume and it is hard to expect that it will resolve without a drainage. However, your surgeon has a full insight in your preoperative and postoperative findings and you should follow his recommendationsDaniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery 
Member, Am. Society of Plastic Surgery 

Seromas are common problems after tummy tuck surgeries,  400cc seroma is quite a bit of fluid and from my knowledge a lot of fluid simply to resolve on its own.    When I encounter these problems I tell the patient to wear compression and see them every few days to get on top of the seroma and let things stick down.  As always, I encourage you to revisit your surgeon as he/she knows exactly what was done and if there were retention sutures placed which could decrease the incidence of seromas.