Toddler has strep for two weeks (this coming friday). temp seems to go up at night to around 100.3 to 100.8. should i be subtracting a degree rectally?

Best not to adjust: Rectal temperatures are most reflective of true body temperature and should be interpreted directly. As a matter of fact, it's best to report the measured temperature with the method by which you took it, and let your healthcare practitioner analyze it's significance. Hopefully your child is on appropriate antibiotics for Strep infection, which should cause fever resolution in less than 3 days.