While you are almost dead and bleeding you need to use a bandage, first aid bandage, or first aid kit.
To get this with little effort you can craft a bandage with cloth fragments from collecting cotton. You will then just need to collect some wood to create some wooden spikes.
After that just place down the spikes and then jump on top until you are almost dead and your character is bleeding out and an icon of a heart with an arrow through it.
If you also manage to acquire some broken glass you can eat, yes eat, the broken glass to suffer bleeding damage but will most likely cause death as you take over 150 damage.