Is it normal that the bottom of my glans, or my corona. is darker then my actual glans head? It's purple and my glans head is pink.
Yes, that is typical. The color comes from the veins that return your blood back to the heart. Arteries, which come from the heart are red in color. Veins are bluish in color. Over most of your skin the veins (except a few big ones) are deeper in your body). In some areas, however, the veins are nearer the surface as so you get a blue tint mixed with red tint, which gives you a purple color overall.