Summarize this article in one sentence.
Do not rub, just blot as rubbing can cause the blood stain to spread or go deeper.   If the stain is still visible, try using hydrogen peroxide. Hydrogen peroxide can bleach your hardwood floor so be cautious when using it especially if you have a dark hardwood floor.   Rinse the area thoroughly to remove all the residues.

Summary:
Blot the excess blood on the hardwood floor with a dry cloth or paper towel. Sprinkle the affected area with baking soda. Dip a brush in white vinegar and use it to gently scrub the stained area. Wipe the area thoroughly with a dry clean cloth. Apply hydrogen peroxide on a white cloth. Scrub the blood stain gently with the cloth. Wipe the affected area with a damp cloth. Dry the hardwood floor using a towel or cloth.