Brief Answer:
Melasma

Detailed Answer:
Hello. Thanks for writing to us at healthcaremagic

The condition which you have is known as Melasma.
Melasma presents as hyperpigmentation commonly over the cheek bones/malar area but also on the nose, forehead, upper lips.
The pigmentation may vary in intensity from light brown to dark brown or even bluish, depending on whether the pigment is confined just to the upper layer of skin/epidermis (light brown) or it involves both the upper as well as deeper layers (dark brown or bluish).
Melasma is idiopathic in most of the cases, specially in males. However, there are a few well known causes of Melasma such as oral contraceptive pills, pregnancy in females and NSAIDs

Sunscreen is an essential part in the management of any facial pigmentation including Melasma. It should be used daily even after your pigmentation has resolved with treatment in order to prevent re-pigmentation.
The sunscreen you are using is quite good. It is broad spectrum i.e contains both UV A as well as UV B coverage.
I would suggest you to continue with it, throughout the day.
Reapply every 2-3 hours.
At night you may use a demelanising cream containing one or more of the skin lightening agents.
These skin lightening agents work by either reducing the synthesis of new melanin Or by exfoliating pre-existing melanin Or both.
The cream which you initially used contains a combination of tretinoin, hydroquinone and mometasone. This combination is a gold standard for treatment of Melasma. However, this combination should always be used under the supervision of a dermatologist. It should never for more than 6-8 weeks in continuity because it can have side effects like acne, skin thinning and photosensitivity etc
Once the desired effect has been achieved it should be substituted products containing one or more of the following active ingredients e.g Azaleic acid, Hydroquinone (2% or 5%), Kojic acid, Arbutin, Glycolic acid, Undecylenoyl Phenylalanine, licorice extract, Vitamin C, etc. These ingredients are safer to use on face even if used over a long term.
Chemical peeling sessions can also be combined along with topical treatment. Chemical peeling alone sometimes may not produce the desired results, therefore it is better if it is combined with simultaneous topical treatment. The peels that are commonly used for Melasma are Glycolic Peel, Kojic acid peel etc. Nomelan Phenol peel is also quite good.
Avene Ystheal cream is not specific for treatment of Melasma and in my view you may discontinue with it.
If I was the treating doctor I would have re-started you on combination of tretinoin, hydroquinone and mometasone for a month or so. Thereafter I would have substituted it with a different cream containing either hydroquinone, kojic acid, Azaleic acid etc.
Of course, sunscreen would have been a part of my treatment.
I would suggest that you seek another appointment with a dermatologist in your region. You can discuss in more about these treatments with your treating dermatologist.
Melasma may take time to respond (may be 4-6 months depending on the intensity of pigmentation) and therefore you have to be patient with the treatment and follow up regularly with your dermatologist.
Your dermatologist might change or modify treatment according to the response.

Regards

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