after reading your complaints i think that your skin is exposed to not only fungal infections but also many sorts of ointments
and local applications. but in your case cause seems to be from within, i mean to say that it is not getting hypopigmentd from outside but from within. as you have not mentioned any other complaints like itching, discharge, pus formation etc. which can help in proper diagnosis i would like to advice you to see a qualified homoeopath who can help you tolasting recovery.
you should also need to look at your food habit. Avoid all kind of junk foods. drink plenty of water, ear fruits and salads. no need to be overly anxious.
wish you helathy skin.