Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain dark blemishes on face and forehead can occur due to a number of causes out of which common ones are:
1.Sun exposure.
2.Side effects of any skin cosmetics.
3.Allergic reactions.
4.Hormonal Imbalances.
5.
Acanthosis Nigricans.
6.Thyroid disorders.
7.Hemocromatosis [increased iron content in body] etc..
You should
consult a Dermatologist and get evaluated and a thorough clinical examination and investigations like complete blood picture, hormonal assy etc can help in diagnosis and treating the underlying cause can resolve the symptoms..
If it is due to any underlying disorder treatment of the same has to be preceeded following the depigmentation treatment..
Hyperpigmentation caused due to excessive melanin formation can be treated with depigmentation creams like those containing Kojic acid, glycolic acid, Vitamin E..
Grapessed extreact, licorice etc can help..
Using depigmenting facewash like those containing
Salicylic acid and glycolic acid can help..
Treatments like
Microdermabrasion and chemical peeling will help..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.