@simrin-- I'm not a doctor but I think if you will be using vitamin K for a skin condition, it's better to apply it topically directly on the areas that have a problem. It will penetrate into skin that way. This is why it is used for dark under-eye circles.
As far as I know, there is no cure for rosacea so don't expect vitamin K to do wonders. However, rosacea causes areas of redness on the face and I think that vitamin K might reduce this redness because of its effects on the capillaries.
You might also want to ask your dermatologist about it at your next visit.