Baby won’t eat

My 3 month old hasn’t had a full bottle since maybe 6 am, its now 1 pm. He’ll take a few sips out of the bottle and then start screaming. He’s probably only drank 2-4 ounces and he usually drinks 6 ounces every 3 hours. We gave him Tylenol and Orajel Incase maybe hes teething and it hurts his mouth to eat. Does anyone have any ideas what to do?