Hi. Thanks for posting your concern at HCM I would keep a possibility of Melasma. Betnovate-N contains a potent steroid betamethasone valerate and it should not be used on face for more than a week or two because steroid related side effects can develop in people who use it indiscriminately for long periods e.g Acne , skin atrophy and telangiectasia, photosensitivity, facial growth specially in females etc. It is anyways not the right treatment for melasma. If i was your treating doctor i would have asked you top use a broad Spectrum sunscreen, which offers both UVA and UV B protection throughout the day. A skin lightening cream at night containing one or more of the following ingredients : Kojic acid, Azaleic acid, Hydroquinone, Glycolic acid, Arbutin etc is a better and safer option as compared to steroids. take care regards