I have very rashes on my private part and it is very painful in Summer when I apply cream and later on it again it get damage in some day.

Rashes in the groin region leads to a lot of discomfort and embarrassment. Fungal infections are the most common cause. A proper diagnosis and appropriate treatment leads to complete cure within a month. Often the topical creams containing steroids are applied by unsuspecting patients that lead to extensive and recurrent infections. I suggest you consult a dermatologist for this problem. Till then, stop using the cream you are using. It may contain a steroid. You can safely use antifungal dusting powders and soaps. Avoid wearing jeans and synthetic clothes. They do not dry easily and further aggravate the problem. Keep the area absolutely dry.

It may be fungal infection due to humid and wet climate. Wear loose and cotton clothes. Keep the private parts dry. Change underclothes regularly use ironed cloths, apply oil after bath. Take anti fungal treatment.