Decadron® (dexamethasone) 4 mg is not the therapeutic equivalent of Kenalog® (triamcinolone acetonide) 80 mg. Using the Lexi-Calc corticosteroid conversion formula, the ratio of the 2 would be close to 5:1. So it would take Decadron® (dexamethasone) 16 mg to be approximately the equivalent of Kenalog® (triamcinolone acetonide) 80 mg.
Decadron® (dexamethasone) is characterized as a "long-acting" steroid and Kenalog® (triamcinolone acetonide) is an "intermediate-acting" steroid. Thus duration of action of Decadron® (dexamethasone) is somewhat longer than that of Kenalog® (triamcinolone acetonide). Along with the lower Decadron® (dexamethasone) dosage at 4 mg vs 80 mg, this may account for the resurgence of your symptoms. You may want to ask your doctor if he can special-order the Kenalog® (triamcinolone acetonide) or would he be willing to increase the dose of Decadron® (dexamethasone).
Finally, both of you may want to consider the substitution of a prescription steroid spray, be it for nose/sinuses or lungs, to provide the same benefit with less risk of side effects.