blood stain on wool carpet

you want enzymes on that. Get some Dynamo liquid laundry detergent (look for the one with enzymes in it – on the labelling somewhere). Drip a few drops onto the mark and rub it in with your finger. It’s important you do that as enzymes have optimal performance at about body temperature. Do that for a few minutes and blot it up with a warm cloth. Might need to do it a couple of times but that should remove it