It could be hair follicles, or something else, but if you think it's infected, you need to get this checked by a doctor. You definitely need to get it checked because it's getting worse.
Don't wait on this. Go to an urgent care if you can't get in with your doctor. The fact that you've had it for a few months and it's suddenly swelling and getting much larger is not good. Get to a doctor soon, like today.