Black pigmentation on my sun exposed neck and hand areas?

Dermatology questions are exceedingly diffucult to answer simply because we cannot see the skin as part of your question. Also, you are using creams and pastes that are probably only familiar to your locale. Look up acanthosis nigricans; is this what you have? If so, you may want to be tested for diabetes, as this is a sign of insulin resistance and thus would not respond to creams or pastes. Otherwise, you should realize that the perimenopausal symptoms may be coincidental.