This how-to is a bit of a cheat. It's a spooky adaptation of my raincloud tutorial from earlier this year... instead of a cloud with raindrops it's a wound with dripping blood!
Sort of gross, sort of cute, and perfect if you don't fancy dressing up "properly" but need to make a quick costume to wear for a party this Halloween :)
Just draw your own wound shape, follow the tutorial for the raincloud to make the brooch and then pin it to your sweater.
For more crafty goodness, check out my books: Super-Cute Felt and Super-Cute Felt Animals.