I've found that the best way to shift whitespot is to turn up the the temperature in the tank, switch off the aquarium lights (I believe that the protozoa use some form of photosynthesis to multiply) and apply the appropriate treatment.
The best treatment I can recommend is King British WS3. Be careful not to overdose, though!
If this is not available in your LFS, I'd recommend Waterlife Protozin.
try melafix or adding aquarium salt .... if you dont do it soon i think it will die
I believe that Melafix is used more to remedy bacterial infections, rather than protozoan parasites.