Just give him tylenol based on his weight and see if it goes down. Repeat as needed. If it lasts more than 2-3 days or gets way to high or he is acting very lethargic take him to the dr.
It depends on how much he weighs as to how much infant Tylenol or Ibuprofen you can give him. Honestly, best thing to do is to call the doctor's office and have the on-call doctor call you back.