miserable baby

Casandra • 27 yrs old married for 10 years 😊we have two kids 9 and 8 and another on the way
My baby got his 4month shots and he's been miserable since he has a fever and he cries in pain I tried giving him baby Tylenol but he throws up 😭 I don't know how to help him anyone have any advice?!?! How long will this last ?