Hydrogen peroxide gets blood out of almost anything. You can use a cotton ball for paper so it doesn’t get all wet. If you get it on clothes just pour a little over the blood. It works if the blood has dried too. It doesn’t work if you washed the fabric in hot water.

I would probably take a q-tip and dab at the blood with a tiny bit of hydrogen peroxide. It might bleach out any color, so only do that if the paper underneath is white. Really don’t use much, and perhaps test first in some less important area of the notebook.

OP do you also need help to hide the body

Blood probably isnt even in the top 5 worst bodily excretements that book has had on it that year. Literally nobody is going to care about teeny red spot on page 231. Dont worry about it.

I doubt you can remove blood from paper. Tear out the page or put cute stickers on the stains.

Scissors.

This is more for fabrics than paper…
For blood stains, cold water is usually better than hot water.
Hydrogen peroxide or salt water might work.
Not sure that you can really remove a bad blood stain from paper.

Try it with pure isopropyl alcohol. No water, because water destroys your paper.

But: it can also remove the ink from your paper (depending on the type of ink).

Paint over it with a black marker.

You can’t remove them, only at best make them fade slightly. That is not enough to prevent weirding people out, which I understood is your goal.

A blacked out area is slightly less weird.

Bleach removes it quickly is strong and you won’t need to get it as wet, but will remove all other color.

Peroxide is safer on other things, but will need to make it fairly damp if you don’t have some 30%

Alcohol will just turn it lighter brown.

I’d test a spot with bleach on a qtip, as little as possible.