Prednisone or spray-on tanning?

I’ve noticed I have had no replies on my halo nevus question, and that bums me out. I do have another question I would like opinions on.

I recently underwent Prednisone treatment for a facial contact dermatitis. My face broke out horribly and my doc put me on Prednisone for eight days - 10 mg., four a day for two days, then three the same, two, then one. The drug therapy cleared up my face and ended July 14.

On July 16 I had a spray-on tan done, and all this week I have noticed that my face is nowhere near as oily as it usually is.

My question is: Does anyone know or have a theory what this may be due to (the steroid therapy or the spray-on tan ingredients)? If it is from the spray-on tanning, I would get one as often as needed! I would really appreciate anyone chiming in on this!