What should I do for minor street dog scratch?

Your skin might be affected by acanthosis nigricans which is identified by dark patches, even on the throat and joints. Being overweight and having high blood pressure are risk factors for this. The treatment is to lose weight and control the BP, as a result, the patches can be healed. Follow a healthy diet, exercise regularly, and be consistent with your prescribed medications to control your blood pressure.

As a vegetarian, if you want to include Omega-3 fatty acids in your diet, you should not use fish oil. What is in fish oil mainly comes from fish, and many people may find this unappealing. Instead, consider using flaxseed oil or algae oil which are obtained from plants. The two oils have similar benefits as fish oil but do not contradict with the vegetarian lifestyle.

Using the cream may have caused your skin to become thin and fragile, a condition known as atrophy. The dark layer you see could be a result of this. Try using a gentle moisturizing cream with ingredients like aloe vera or oatmeal to help fade it over time. Avoid strong products and give your skin time to recover. Always do a patch test on new products before applying them to larger areas. 

You expe­rienced an unwanted re­action to the serum. Pee­ling, dry skin often results from overusing harsh products. Stop using the­ serum right away. Prioritize gentle­ moisturizers, avoiding irritating formulas. Allow time for natural healing. Ove­r a few days, your complexion should improve and re­gain balance.

Pimple marks are small bumps that can be red, swollen, or have pus, the pinky-gray of the skin. These things are generated when the pores become clogged with oil and dead skin cells. Pimple marks are dark or red spots left behind after a pimple goes away. In order to reduce your chances of getting pimples, you should wash your face regularly, stay away from oily products, and never pick or squeeze the pimples. Apply products that contain benzoyl peroxide or salicylic acid to treat them.

There are many treatments for acne dark spots like chemical peels, laser treatments, certain ointments etc. But I suggest you to first visit a dermatologist in person. Based on your individual condition, the doctor will be able to recommend the best treatment for you. 

Skin melanin treatment surgery can be harmful in the long run so I suggest not to go for it. You can try other treatments like chemical peels or dermabrasion instead. These treatments can help lighten the skin and are not harmful in the long run. Also using moisturizer and sunscreen can help.