I'm an Asian and I'm going to be 21 soon. I am very unhappy with the size of my penis. It's only a few centimetres when it's flaccid and about 3.5 inches erected. I also have trouble retracting my foreskin. It hurts when I do it and when my penis returns to its flaccid state after masturbation, it is difficult for my retracted foreskin to go back to covering the head of my penis because the foreskin sort of gets stuck at the base of the penis head. I'm really embarrassed about my penis. Please help