I have dark pigmentation all over my neck and face. I have tried many types of facials, without result. Is there any effective treatment for this?

Facial pigmentation can result from sunlight or the use of cosmetics. In many sensitized individuals the combination of cosmetics and sun exposure, can result in pigmentation that may take a long time to fade away, even with regular treatment. Facials will not help the condition, on the contrary they may worsen it. At the outset it is necessary to identify and avoid the suspected agent. There are a number of lightening agents containing hydroquinone, azelic acid and kojic acid that will help treat it. Wear sunscreen at all times.

I have a persistent itching problem near my vagina for last one year, esp on the exteriors of the flaps. When I applied Candiderma cream in the area the itching stopped for a while. However, last month I again felt the sensation. I now lubricate those areas either with coconut or olive oil on a regular basis, otherwise it gets dry, turns red and develops cuts. During menstruation its fine. Till date I have no problem with passing urine. Sometimes I also notice a white velvety coating in those areas. Is it an early sign of diabetes or anything serious?

From the description of your symptoms it appears like you have a fungal infection, but without an examination one cannot be certain. It would be ideal if you can consult your gynaecologist at the earliest. Meanwhile you can
1. Get a blood sugar test done(since you have family history of diabetes).
2. Take a course of oral antifungals like Forcan 150 mg, one tablet once a week for 3 weeks, when you notice the white  flaky discharge.
3. Apply Canesten S cream after washing the area, twice daily for 7 days.
4. Drink plenty of water, buttermilk or curd to improve the pH balance in the area and allow good bacteria to grow.