Ridge at bottom of chest

[Deymorin]

Hi guys
Had surgery 3.5 months ago

There's a ridge both sides, under my chest. Just above my ribs.

I've massaged away most of the scar tissue under the nipple e.t.c but this just seems to bruise when I massage it hard. I'm pretty sure I didn't have it before the surgery, any ideas if it's scar tissue?