>>16779535 (OP)
this is a keloid(raised scar) granuloma(growth) that can happen as a reaction to suture material. Although, they likely used "prolene"(fishing line, basically) that is usually quite inert, but reactions can still occur.
It looks like it may be getting rubbed every time your arms swings by, which could be causing the redness.
you can use a topical hydrocortisone cream to reduce the swelling, but it doesn't appear to be spreading to the surrounding areas, which would indicate infection.
you may even be able to simply text a pic to your primary, or the surgeon, to see if they think there is any reason for concern, but I doubt.
A chest tube is a bid deal, Anon, so it may take time to heal.
If it gets more "angry"/red/irritated, go see your doc and ask about antibiotics, but we try not to use those more than needed these days, if we can help it.
This is not medical advice.
