At 10 years, a one-sided rounded area should not automatically be attributed to scar tissue. It could reflect cartilage or bone shape, soft tissue, a mature scar, or normal asymmetry, and these cannot be distinguished from the description alone. Kenalog (triamcinolone) may help selected hypertrophic or actively thickened scar tissue, but it is unlikely to reshape cartilage or bone and is generally less likely to improve a stable contour issue this long after surgery. An unnecessary or overly deep injection can cause skin thinning, a visible depression, telangiectasia, pigment change, or worse asymmetry. Have the area examined and palpated by your operating surgeon or a board-certified facial plastic/plastic surgeon before considering an injection; the exam should also assess your breathing and compare both sides. If the issue is structural, revision may be discussed, but only after the cause and realistic benefit are clear. I would not inject based on an assumption of scar tissue.