If it's still tender today when you apply pressure and an antihistamine/motrin combo doesn't help with the redness, then go to a doc. You don't have any old AB's on hand? Except tetracycline, never use old tet. Other than that, I'd suggest a ceph. if your not allergic to pen. It works fast and is usually good for these kind of infections. But quickly getting to the doc is always best. It's often just a type I immune response if no swelling is present w/ the redness/hottness/hardness.