Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain it seems that darkening of skin of face, neck , arms and legs is due to sun exposure causing
tanning as well as these areas are exposed to pollution, chemical, heat etc..
The first thing that has to be done is to limit sun exposure and always apply a SPF 50 containing sunscreen lotion when exposed to sun and you can also cover your face with a scarf and wear gloves in hands for protection..
You can apply
Kojic Acid containing creams on face to reduce pigmentation..
Wash your face frequently throughout the day..
Use
Salicylic acid and
glycolic acid containing facewash like AHA glow, melaglow etc..
Exfoliate the skin of face, neck , arms and legs with a face and body scrub..
You can also go for pedicure, manicure and regular cleanup or facial..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.