Would Kenalog injections reduce the size of my lips which have enlarged due to sucking them?

Kenalog doesn't give predictable results and isn't good for lip reduction. Lips can be reduced with surgery, pdo nova threads and lasers to improve shape. See an expert in facial sculpting for a formal evaluation. Best, Dr. Emer

Kenalog can and will kill fat.  However, it is terribly unpredictable.  This is not a safe approach.  Please consider posting photos.  It is possible to reduce the lip size with mucosal surgery.  Caution is advised.

Without at least photos, it is really difficult to say whether triamcinolone acetonide (Kenalog) injections would play any role at all in helping to resolve your problem. Kenalog is traditionally used to help shrink and flatten elevated, protuberant scars, such as hypertrophic scars and keloids. If, in fact, the repetitive sucking of your lips led to some form of tissue trauma and scarring, then perhaps intralesional Kenalog may be of value. The adjunctive use of hyaluronidase to help more evenly disperse the Kenalog may be additionally helpful. You would do well to seek consultation with a board certified aesthetic physician. My very best.