I hit my cheekbone hard on the corner of a marble nightstand three and a half days ago. no bruising but swelling and a hard lump that is very sensitiv?

Hematoma: Most likely there is a collection of blood on the bone surface called a hematoma (or what my mother called a "goose egg"). It resolves gradually over a week or 2. If you hit the area between the cheekbone and the ear (zygoma), it's possible to fracture that, and a fracture could result in long-term cosmetic defect. If concerned, see your doctor and x-rays could rule out a fracture.

Conservative care: If you are not having any ifficulty or severe pain when trying to talk,chew,smile,or make other facial movements making your life difficult,I would recommend frequent application of ice for15-20 minutes at a time to help with swelling and pain,as well as taking an anti-inflammatory pain reliever such as ibuprofen or naproxen.I expect pain and swelling to decrease over next 7-10 days.See doc if not