If the pain gets worse but the swelling doesn't by tomorrow you should be OK.
The chances are, because it's hard, you ruptured a vein by putting the oil in too close to it and bursting it with the oil pressure.
This usually gets more painful over 72 hours and then drops off. If your swelling gets worse then it may be infected. But that usually takes longer than it did for you to get started. If you have antibiotics start taking them. It can't hurt.