Hello and Welcome to 'Ask A Doctor' service. I have reviewed your query and here is my advice.
Mometasone is a steroid based cream and at times ot can cayse dark spots or increasing pigmentation as a side effect.
Now as per your complain Melasma leads to formation of brownish to black patches over the face and occurs commonly due to hormonal imbalances..
It can occur due to causes like:
-Intake of Birth Control Pills.
-Pregnancy and child birth.
-
Hormone Replacement Therapy.
-
Hypothyroidism.
-Exposure to UV rays ia overexposure to sun.
I would suggest you to
consult a Dermatologist and get evaluated and he can do a thorough clinical
evaluation and investigations like Wood Lamp's Test, hormonal assy and at times Biopsy to confirm the
diagnosis..
Melasma is slow to respond to treatment and generally the
depigmentation creams can lighten the
pigmentation and does not resolve it completely..
In case if it is due to hormonal imbalances correction of the same can help..
Cessation of hormone replacement therapy if you take any can be helpfum in improvement..
Limit sun exposure and always apply sunscreen lotion when exposed to sun..
As a part of treatment you can be advised
Hydroquinone containing creams..
Azelic acid and
Kojic acid containing Creams are helpful..
Vitamin C oral as well as topical can helpful..
Metamizol containing ointments can also help..
Hope I have answered your query. Let me know if I can assist you further.