if it stays red for more than a couple hours, or crusts around the edges, or oozes green, or yellow, then theres a possibility you have pink eye. keep it cleaned off, and if it crusts up or stays red and/or swollen, then i would recommend going to the doctor. be sure to keep washing your hands before and after each time you touch your eyes for at least 20 seconds.
Is the red, Blood Red? As if you may have broken some capillaries?
Also have you been vomiting,coughing, or crying extremely hard recently?
When pressure builds up in the eye, it can sometimes cause those little blood vessels to burst. It will look like blood, Not just a red irritated eye. Please let me know.
The best thing to do is see your doctor!