White specs that appear on a print are most likely the result of debris or dust that falls off after printing. Cotton based paper is more likely to experience this issue compared to other types of inkjet media. Cotton fibers are rough and can either break off or trap coating loosely, which falls off when handled.
You can mitigate the problem by doing some prep work before printing. A Quick Burst of Canned Air or Brushing With an Anti-static Brush usually removes any debris large enough to make noticable specks.
Another option is a compressed air blower which replaces canned air. Once such product is the EasyGo Products - Compu Cleaner. We would consider this for those making many prints, especially large cotton fine art prints.
Finally, photographic touch-up inks can be used to make small corrections and fill in white spaces. Originally for darkroom print correction, they are still available (though maybe not for much longer) and work fine on your inkjet print. There are different sets available that include different color choices.
If you give these a try, keep in mind it is ink and brushes and requires a steady hand and probably practice.