Hi, I can understand your concern for the sudden flushing on face. You have not mentioned your age, sex and occupations along with other details so that hte most probable diagnosis could be made. After reading the query, in my opinion it appears to be Allergic dermatitis: There is sudden redness and itching on contact with a particular contact allergen. It is not sue to prednisolone as this is basically used to treat this kind of problem. I suggest you to apply medium potency steroid cream application because are best effective in these condition. I would have opted for either mometasone or Fluticasone or cortisone cream. Do not pinch, pop or scratch or even touch the area unnecessarily as it can cause aggravation of the rash. Stay away from extreme of hot, cold and sunny environment. It would be best to consult a dermatologist for the best possible cause. Take care.