Have had a lunp undermy skin on my cheek for monthsand now the last couple days it a bit bigger but looks like a red zit now but cheek is veryswollen?

Go see your doctor: If your cheek is swollen, you might have an infection which would require antibiotics to settle down. But an examination by a doctor is essential before you get into more trouble with your lump.I would not delay this more than a day or two or you may be better off going to an emergency room although that is an expensive way of handling your problem which can be managed if you go to an outpatient.