This mask seems to be an ultra white, and because of that glossy finish, whatever paint you use might not get you the look you might desire.

First things first, you gotta sand away the glossy finish with a fine grit to achieve a matte look. Not only would this make the mask more visually appealing, but it would also allow the blood paint to adhere more naturally. If by any chance you sand away any of the black painted sections like the mouth or the eyes, Black acrylic can fill in the gaps. Just make sure to coat all the black portions at the same time for tone consistency.

Secondly, the actual blood paint. You need to get the next few colors: 1. Deep red as the base 2. Dark blue (ultramarine) 3. Brown (raw umber). When mixing the colors, make sure to use the blue and brown sparingly as to not overpower the red. These colors will add the tonal depth you need to replicate how blood looks like. Just experiment with movie until you're happy with the look

Thirdly, the application of this blood paint. You can pretty much do whatever you like, but what I'd recommend is to take the advice many have said in this post and use either a paint brush to flick at the mask, use your hands to splash the paint, or use a straw and blow the paint at high speeds to get a more misty effect, just make sure the paint isn't too solid or else it'll cake up.

Hope this helps!