My 7 month old son has no signs of being sick. he felt warm so i took a rectal temp and it's 102.3 i just gave him ibprofen. when should i take to er?

Fever: If he becomes irritable and refuses to eat, I would then take him to the ER.otherwise, symptomatic care is in order. He may be incubating Roseola where kids run fever for three days, the fever breaks , and the child breaks out in a measles-like rash

Fever: Continue to watch him, and give ibuprofen. If the fever hasn't resolved in 24-48hrs, have him seen. Make sure you force fluids. If he seems to be getting worse, fever that doesn't respond to ibuprofen, very irritable or very lethargic; have him seen sooner.