Bad news. You need to take it out at once!
If the swelling has spread, this is likely a sign of infection. You don't want to mess around with infections around your head, neck and main arteries, as they could have serious consequences.
Unfortunately, it's bad news for your piercing too. Cartilage piercings are notoriously bad healers because they don't receive as much blood flow as other piercings such as the lobe.
That's why, even though you've had the piercing in for 3 years, the change of hoop probably let some bacteria into your body, and this caused the complication you're dealing with now.
I had a similar experience.
Back when I was young and trendy (there was a time), I had a stud through my cartilage and wanted to link it up to another piercing using a "scaffold".
I looked awesome for a while, but I guess the continuous movement that a bar like that would involve meant the piercing never fully healed, and was susceptible to infection.
My ear started swelling up and becoming uncomfortable, so I decided to take it out and let it heal.
Unfortunately, I also developed some scar tissue around the healed area, and this meant I couldn't have it re-pierced once the infection died down.
You also need to be careful with multiple cartilage piercings, as I've heard horror stories of the cartilage splintering or shattering inside the ear!
All in all, it sucks to lose a piercing. But you can always get something else pierced instead to replace it...
When I had to lose my scaffold, I got my bridge pierced instead: