From what you are telling me, a cat must have bitten you. And even though it didn't bleed, you saw a burning sensation and a red dot after the event. This is a possible result of bacteria from the cat's mouth. It is important to wash the area with soap and water. Check for any swelling, pain, or redness. If you see anything out of the ordinary, don't hesitate to see a doctor.

The numerous factors that lead to skin allergies on the backside and legs include irritants, allergenic agents, infection or autoimmune disorders. It is necessary to consult a dermatologist that will conduct sufficiently comprehensive evaluation and suggest adequate options for treatment. Self-diagnosis and self treatment can make the situation only worse complicating it.

Without a proper evaluation and diagnosis, I can't say. But normally, suggested treatments for perical pigmentation include topical medications and laser treatments and I do not recommend flutivate cream for pigmentation. However, based on your individual condition, the doctor will recommend the best treatment for you. 

Hair loss can be caused by stress, hormonal imbalances, or health issues like PCOS. In your case, the shedding might be related to these factors. The good news is that it should improve as your menstrual cycle regulates. Eating well, managing stress, and self-care will help your hair grow back stronger. 

Sometimes not having enough vitamin D3 can cause people to lose their hair. You should keep taking the vitamin D supplement as the doctor told you. You should try to eat more foods that have iron and protein in them as well. One thing that might help is finding ways to relax when you are stressed. 

Pigmentation is triggered by different factors such as genetics, sun exposure, and hormonal changes. A balanced diet rich in antioxidants and drinking a lot of water may help improve skin health. You should consult a dermatologist for proper diagnosis and treatment. They may prescribe an appropriate medication and recommend certain lifestyle changes to control pigmentation.
 

Finasteride is mostly safe to use for most people and it's not a direct cause of prostate cancer. Nevertheless, it can have an impact on the behavior of the prostate which in turn, may result in a PSA test result being altered. If you have concerns, it's always best to talk to your doctor.