fake blood packet

I know wrestling is fake but how do they do the blood?
Is the blood from wrestling real(like what Rated Rko did to DX a few weeks ago) or is their like time release blood packets or something like that? No rude answers please. Thank you.
they hide a blade so the fans wont see it and then they will cut their foreheads and their blood will mix with their sweat and it looks like they are bleeding a lot.
Skateboard accident