Do you breastfeed him? If so he will get antibodies from you so he could get better faster! If not do not fret, his immune system will still get a boost from fighting an infection! Just keep a close eye on temperature and temperament and call or take him in to the doc if something seems off or if you're just overly worried!!!
As long as his rectal temperature is okay, he should be fine mama! Definitely ask yourself this though: Is he still alert, feeding normally? Is he acting differently? More upset, or too sleepy? Does he have any ither symptoms? And also, is your thermometer accurate? If all these things check out he should be fine, if you're not sure try calling a nurse's hotline (most pediatricians have them) and ask for advice, they can help you figure out if he should be taken to the doctor. Keep in mind that babies sometimes just run hot, my baby girl sweats like crazy when she nurses sometimes but her temp is fine and there's nothing wrong with her!