I fell into a huge patch of nettles while riding near Jedburgh once. Got stung all over my legs. It wasn’t much of a problem until the ride was over and I was getting a lift home. Then it was like the entirety of both legs were either buzzing or on fire. The nettle stings I’d experienced before were nothing in comparison. I tried to stick it out but I only lasted until lunchtime the next day when I made a dash from work to Boots for anti histamines and witch hazel cream.
On the other hand I don’t find that gorse thorns tend to stay stuck in me when I get spiked by them, so while they’re initially painful it’s not a lingering pain like nettle stings are.