This site cannot diagnose illnesses, diseases or pregnancy over the internet, nor is it the purpose of this site to do so. The best that can be offered is advice. If you are truly worried about your condition then seek medical attention.
Irritation
scale
Wheal
It's probably Intertrigo. Remedy takes time.
Your cat probably has a hot spot...just an itchy spot that may have dry skin. I'd get that checked out.
Yes, the sun spot affects the durablity of your skin making it easier to result in skin cancer.
Most of the time? No. Could it be? Yes. How can you tell? SEE YOUR DOCTOR.
Skin cancer is VERY rare at that age. But if you have a suspicious mole or spot that seems to be changing or getting larger, see a doctor (dermatologist).
It may be an ingrown hair. There will be a loop of hair on the bump, pluck it and then your good.
Your dermis has a slight black spot. I think you have cancer.
Should I see a skin specialist
The black spot will not go away as it is the eyes of the fry through the pale skin of the guppy. As the pregnancy progressess, the (black) gravid spot will get darker, and the fry will mature.