Hi, I have been using differin every alternate nights for 3 months without problems. But just last sun, I rubbed some onto my eyelids and facial rashes started to explode. They were not itchy at first but started to spread and becoming very itchy. My Gp said its contact dermatitis. But how could it be as I have been using it for 3 months? I put hydrocortisone cream on them but nothing seems to subside. Now my whole face is covered with itchy swell rashes. What should I do? Could I become allergy to retinol out of a sudden?