This reaction could be due to anything, like the cortisone calming some prostate minor inflammation. But it's evident that doing it again and again will do the exact opposite, it'll f**k up your endocrine system, we're talking about hormones and steroids here. It is still likely that you'll experience it after one shot. Desired effects of cortisone are very short term, but it generally f**ks you up on the long term with even small doses.
To all of you experiencing problems after cortisone shots, focus on an endocrinologist and have global hormonal check (cortisol, testosterone, thyroid function etc.). A good endocrinologist should be able to help you regulate those levels if something abnormal, it should be of tremendous help. Cortisone is sh*t. sh*t to the square. I don't know how doctors still prescribe it in the US, they never do it Europe except for terminal cancers and the like, not exaggerating. A doctor in France or Germany won't give you a cortisone shot not even if you beg for it. I had a broken shoulder 10 years ago it healed with time (2-3 years) and physiotherapy (and stopping sports in that while....). The sports doc in Paris refused to give a cortisone shot in the tendon. Modern medicine is no amateur game.