Where do you see the flap of skin? Just where the mouth cavity ends? On the upper side? Do you have sore throat, cough or any other symptoms?
Please read this resource and see the photographs in it. Is it looking like uvula? A swollen uvula may sometimes look abnormal.
Please feel free for your follow up questions.
Uvula is a normal structure and do get swollen in the infections of the throat (pharyngitis). They are usually viral and take 3-5 days do get better. Warm saline gargles, 3-4 times a day would help you, in relieving the symptoms. If you have pain or fever, taking Motrin or Tylenol would be helpful.