It’s common to get gray hair early, especially if it started in your teenage years. This can be due to genetics, stress, or diet. While it might seem worrying, gray hair usually isn't a sign of a serious health problem. You can choose to use hair dye or embrace your natural look. Remember to eat a balanced diet, manage stress, and take good care of your hair.

Your skin has lost its radiance. Dullne­ss occurs when your body lacks hydration, rest, or nutrients. Incre­asing water intake, getting prope­r sleep, and consuming fruits and vege­tables can revive your glow. Additionally, ge­ntle exfoliation remove­s dead cells, uncovering re­newed skin underne­ath. Don't neglect sun protection; use­ sunscreen. 

I can see that scratching you due to a street dog can be a worrying issue for you. From your information, the scratch is not too deep, which may mean there is a low chance of infection. Watch out for any redness, swelling, or warmth around the area. First of all, wash the scratch using soap and water and then apply the antiseptic cream to the area to avoid any further infection. Watch the scratch for a few days, and if you spot any of the infection signs that are getting worse, like more pain, redness, or pus formation, it is better to go to a doctor. 

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. 

You may have some skin issues that can be tough to deal with. If your skin is sensitive and oily, try using mild products without perfumes. Possibly, dark spots, skin rashes and pigmentation could occur due to irritation caused by harsh components in the product you are using. Go for products labeled as non-comedogenic so that they do not block the pores on your face. Also, look for ingredients like niacinamide or hyaluronic acid that will help calm down and moisturize your skin. Always do a patch test before applying any new product to prevent unexpected reactions. 

Itching on cheeks, hands, and back could be due to: 
- Dry skin
- Allergic reaction 
- Eczema or psoriasis 
- Bug bites or hives 
- Medication side effect. 

Try moisturizing, avoiding irritants, and OTC antihistamines. If symptoms persist, see a dermatologist.