Few white patches on body. Me doctor.

Doctor i have 2small white patches on my back..nearby neck area..since 2010..at that time only i had consulted an experienced dermatologist in my locality..so he said nothing to worry this wont spread..and i applied melgain lotion,few other ointments also and it ws very effective the size has become smaller than before and it ws stabilised for years not spreading.....but about 9-10 months ago i found 2more small patches on my penis...and i searchd on net and found dat it cud b penile vitiligo..but d images of penile vitiligo ws terrible..i hav only small patches on my penis...now m rly tensd whenevr i see any white dots or nythg lik dt on my body i feel tensd...doctor kindly please tell me whether it ll spread to othr parts of my body or not plssssssssss tell me doctor.......awaitgh for ur response Mny thnks before