Is it possible to devolope a seroma almost 5 months post surgery at one of the hernia sites?

Highly unlikely: You should have the collection evaluated asap. See your surgeon and a ct scan or an MRI may be needed. Good luck from nyc.

Likely recurrence: Recurrent hernia surgical site swelling following resolution of postop changes is recurrent hernia till proven otherwise. If you have focal discomfort, you need to be seen. Get a second opinion if you have to.

It is possible: The development of a lump at the site of a previous hernia repair can represent a seroma, left over contents in the hernia sac such as fat, or a recurrent hernia. I have seen all three of these in my practice over the years. You should see your surgeon for a physical exam, and may need a ct scan. If you do end up having a ct scan, there is no need for an IV or oral contrast. Best of luck!