Is it a stye even if there is no bump on the upper eye lid and it just puffy/swollen?

Possible: Could be the very beginnings of a stye. Usually when caught early when it just inflammation, a chronic stye requiring surgery can be prevented. See your eye md.

Before it becomes a: Bump, the oil glands can get clogged and cause the puffy swollen lid. Warm compresses will help, and like a pimple, the area might come to a head. If there is no improvement after about 3-4 days, see your eye doctor for extra help.

Eye infections: No. It is often a cellulitis. A stye is a particular kind of eyelid problem but not all of the eyelid problems are styes.