7 month old baby fever between 38.3 & 38.9 since 11am. just had second empaped. still 38.3. at what stage do i take him to doctor?

And what else ?: A kid with low grade fever can be watched at home if they continue to feed/drink well enough to remain hydrated. Making pee every 6 hours is ample sign of good hydration. If the kid is playful & retains most of their routine it is a good sign. Any kid who refuses to drink, play or seems restless deserves a look over regardless of their temperature.