Hi..thanks for your query
There is a possibility that you have developed Melasma
This condition is aggravated by UV light sources, sun maximally.
Please wear a sunscreen with broad some thrum of action during the day time.its is important to use umbrella and reapply the sunscreen 4-6 hourly.
You can use a combination of hydroquinine, mild steroid
on the patches at night for 6 weeks. following which you should review for the further line of therapy
Melasma is a very chronic recurrent condition.hence I would advise you to start the treatment by visiting a dermatologist
Hope this helps ...take care!