Skin, Hair and Nail Problems

From last 2 months I have seen change in colour of my nail. It's getting darker at some areas . I have been using nail polish n nail remover . I am attaching the photo of my nail. Kindly help .

I have pcos and insulin resistance. I have dark velvety skin on my neck and armpits and inner thighs. My neck has been like that since I was 14. I have never sought treatment for it before. But recently in 2017 I got diagnosed with pcod and realised the reason behind these dark patches as acanthosis Nigricans. What should I do for treating this condition. I am on medicine (krimson 35) for pcod. Please suggest

Age 24 I have been experiencing dandruff for about 3-4 years. But nowadays I am experiencing  heavy dandruff and severe itching on my head. Please suggest some shampoo or remedy for the dandruff and itching. Some hair fall is also there .About 20 hairs a days.

Itchy red skin in my scrotum.What is this skin condition called.I am worry about this.Please help me, please 🥺😭

Since last night I have observed red Rashes on my arms legs and face it was very less last night today it got increased.

Is the "Havglo"  cream by Intas safe for skin? And can we use this alternatively with tretinion cream

One can discontinue treatment once his/her hair grow back, or will it has to be continued to prolonged period or lifetime?

It is painful and burning my skin. What is happening???? I never had such experience before. I go out in the sun it burns even if I touch it burns and pains a lot.

I've some dark patches on the nose and the cheeks. Any treatment for that? Kindly advice so I can take a consultation

These dark spots are around whole neck ,what can be the possible reason and solution for it .please suggest.