I'll be getting a skin rash regularly on my left hand. I see it a lot in summer time. Currently I'm using mometasone furoate cream ip but no result as?

It's not working. You are using a corticosteroid cream, helpful in eczema's and general dermatitis. If not effective this suggests the rash may be due to something else, perhaps a fungal infection or a symptom of another disease process. See a dermatologist, get a skin scraping and then you will know for sure what is the cause and the appropriate treatment.
See a dermatologist. If this only occurs on the left hand there may be something your are wearing on that arm or touching with that hand which you do not with the right hand. Without seeing this and getting more history, cannot diagnose. Please see a dermatologist.