Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern.. As per your complain Melasma leads to hyperpigmented areas over the face and is most commonly due to hormonal imbalances.. It is also seems in women undergoing hormonal replacement therapy and in cases or due to allergic reaction or side effects of medication.. Stomach ulcers or Gastritis does not seems to cause Melasma.. As far as taking depigmenting treatment is concerned Deriva CMS gel contains retinoid Adapelene and Antibiotic Clindamyicn.. It can be used for long term but unnecessary use of clindamycin that is an antibiotic is not needed.. Hydroquinone is carcinogenic and it is a true fact.. I would suggest you to use safer depigmenting formulations like creams containing Kojic acid, glycolic acid and arbutin as it is safe for long term use.. Apply Viamin E gel at night.. Exfoliate your skin twice a week.. Take Vitamin C suppements.. Limit sun exposure and always apply sunscreen lotion when exposed to sun.. You can also go for treatments like Microdermabrasion and chemical peeling.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora..