Suggest Treatment For Phenomena Fever In An Infant

okay i have an 8 1/2 month old baby he had a cold and sinus infection that got taken care of. For the last two and a half weeks he has been on tylenol because he has had high fevers we went to the emergency room yesterday and they said he had penoimna. He has been on the medicine for over 24 hours and his fever is still 101.9 and hasnt gone down at all now he has a running nose again and dhirrea. Should i go back to the emergency room??