What can cause blood to accumulate on a spot in your eye then spread after a while? and how can be done in that case?

Hemorrhage: You have a subconjunctival hemorrhage. This is a minor seepage from a vein in your conjunctiva (the lining of the eye over top of the white sclera). This will spread for a few days and can be quite dramatic but your eye will steadily remove it and restore the normal appearance. These are usually benign unless they reflect trauma or underlying poor blood clotting. Have patience; it will clear.