I really can't tell very much from the symptoms you describe. Warts are firm bumps, often with a rough or "cauliflower" appearance; pimples are pus-filled bumps, i.e. zits. Cracking, flaky skin sounds different from either one.
Bottom line: I haven't a clue what the problem is, and in any case I can't ever make a definite diagnosis from a written description--although it doesn't sound like any STD. You'll need to see a health care provider, perhaps a dermatologist.
Good luck-- HHH, MD
HHH, MD