Fissures in the nipples without any discharge is mostly dryness. Do you have any flaky growth over it suggesting fungus? If so apply antifungal ointment with the advice of a dermatologist. Are you staying in very cold area or very dry area? Do you have in general dry skin? Have you started your sexual life? On this the advice may alter. Local application of soothening agent will give you some relief. Initially, you may add some antibiotic cream to it if the lesions are painful. Any cold cream is fair enough. I would advice you to go for the natural cream of the fresh milk. This heals the nipple wounds quite effectively. If there is too much of handling of nipples, give them rest for few days. I would advice tou to include vitamin A containing food in your diet; e.g. carrot, beatroot, green and red leafy vegitables. Also consume good amount of citrous fruits in your diet. Vitamin E also will be useful for you. Let your inner clothes covering the breasts be smooth. In fact you can saty in the house without them.