Scar tissue around my belly button from a seroma after my tummy tuck - how do I fix it? (photos)

That area needs to be excised and let heal. You may have a fairly thick capsule inside from the fluid, and that thick scar tissue may not go away on its own.

First and foremost you should get confirmation that there is no active infection in your belly button. If there is then it needs to be treated. This means there should be no opening, no drainage and no fluid coming out.
Typically the first sign of an infection is increased tenderness and pain.
Areas that have ongoing persistent increased inflammation such as smoldering infections with contaminated suture material can develop excessive scar tissue formation.
Well it doesn’t sound like you’ve had issues with having an umbilical hernia that also can cause a protrusion of the belly button.
Internal scar tissue will continue to be created as long as there’s an inflammatory process going on such as smoldering infections.
The same scar tissue will eventually shrink, reduce and soften with time once there is no inflammation in the area.
Excessive scar tissue can sometimes be managed with injection of anti-inflammatory steroids.
Just generally not to be done until they are young has been healed and at least 6 to 12 months have gone by to see how much it’ll prove on its own.
If there is any evidence of ongoing medical issues like an infection or fluid collection then these must be treated first.
Continue following up with your provider. If you’re not getting the care you need to consider getting a second opinion consultation.
Best,
Mats Hagstrom MD