definitely not a stye (like you can see on the picture at the internet link that's only a small bump). Also not a clogged tear duct (can not swell that big, is only at the nose side.) Both things would never cause swelling on the upper eye lid.
Sounds a lot like an allergic reaction, with all the swelling. I would wait one day, if the swelling has not gone by itself I would contact a docter. Often you'll never find out where you're allergic to. Try apply cold compresses.
An infection has 5 thinghs how you can recognize them:
Red, Swelling, Hot, Pain, disfunction of the body part.
You've only the swelling, so its probably not an infection.
But if you're unsure, just contact your doctor. I'm only a optomotrist.
good luck, and let us know what happens next. I'm intrested!
I.