Today after applying my sunscreen, my nose became red,this redness gradually fades after 2 hrs, then i reapplied it again and redness appeared again!!

Sounds like a problm: This sounds like there is something in the sunscreen that your skin is sensitive to. Look at all the ingredients, there may be one fragrance or chemical that differs from other products you have used, and should be avoided. Consider doing a patch test (sample on bandaid applied to an out of the way area for a day) on any lotion or cream you use before applying it to your face.