Ihave had a small hard lump on the surface of my cheek that grows a hard white pimple like head for 4 months. I scratch it comes back?

May be a skin cyst. A bump on the skin that has whitish stuff inside, but is not pus as in a pimple, is likely a skin cyst that contains skin oils and skin cells. A primary care doctor or a dermatologist can look at it to see what can be done. Sometimes, keeping the cyst empty for a while will allow it to shrink in size. Other times, a bothersome cyst needs surgical removal.