Skin colour change could be due to tanning (most commonly) or other causes can be lichen planus pigmentosus or acanthosis nigricans or addisonian pigmentation - there are antioxidant therapies like glutathione , lasers for rejuvenation, PRP therpy for facial rejuvenation , peels, etc. Hair on not required places will need to be examined. Treatment for pimples depensds the number and type of pimples. Black spots under the eye need to be examined - if your referring to undereye dark circles or marks of previous lesions. You can send a picture through online consult so I can get a better understanding of the problem; or you can a qualified dermatologist in your vicinity. Hope this was helpful.