Most likely it would be red and swollen. There may be some drainage and probably some pain. Do you know what caused it? You might try soaking it in some salt water, and if there's an opening somewhere, put a little antibiotic ointment on it. If you are running a fever, or the swelling becomes worse, or the drainage is dark yellow or green, you will need to have it seen by a doctor.
Hope that helps,
Kerry