Hey, congrats on the wedding. I'd like to wish you the best.
I'm in the process of trying to recover from a cortisone induced flare of my palmoplantar pustular psoriasis so I decided to wander over from the thyroid board to see what others were into.
I had a systemic injection of Kenalog 60 and I'm at the point where I would really like to strangle a dermie. He assured me nothing would happen. 3 weeks later, he declared me cured. My hands looked wonderful. At week 5 they exploded. I've visited many psoriasis boards the past couple months. Some people flare, some people don't. It seems that the people who continue to use very mild treatment after the injection seem to last out longer before they flare, if they flare at all.
What I would suggest is to stop stressing over it. You've got enough stress on your plate as it is and stress is a known trigger for a psoriasis flare. If it was a long acting steroid injection, it should get you thru the wedding. And probably the honeymoon too!!!
Take a chill pill and enjoy the upcoming event. It's the union itself that's important and not the outside appearances of things. Just try and have fun and enjoy it.