How long after a kenalog (triamcinolone) injection will my menstrual cycle return to normal?

It is not related: Kenalog (triamcinolone) is an injectable steroid. This is used for many reasons, but not regulating your period. You need to see a qualified gynecologist.

Within 2-3 motns.: Kenalog (triamcinolone) is a long acting steroid that may result in some irregularity of menstrual cycles. It may result in some spotting and changes in length or amount of flow for a couple of months, but then the effect tapers off and normal cycles should resume.