Fever Post MMR jab 2nd dose

I totally understand the worry, because when my daughter had her MMR, the fever lingered longer than I expected too and I was checking her temperature every few hours. From what I recall, some children do run a fever for a bit longer after the MMR, but by Day 6 it really is worth bringing your son back to see the PD just to rule out anything else going on, since the nurse's timeline has already passed. My PD told me that if the fever persists beyond what was expected, it is always better to get it checked in person rather than wait it out at home. Hang in there, you are doing a great job monitoring him closely, and hopefully he bounces back very soon.