Yep, I think you got stung by the stinging nettle. to bad you burnt it. It is a great compost accelerator and also great for making compost tea with to feed your plants. I have stinging nettle growing all over my garden and I've come to love it and actually harvest loads of it for soups and I've even made smoothies out of them. - they lose their sting when mashed up. If you have any of the herb plantain around you can take a leaf of that, mash it up and rub the juice of it where you got stung and it will take the sting away. I use it all the time.