I'm taking cephalexin 500mg that is also and antibiotic. and oxycodone/acetaminophen 5-325mg. right now i have a fever of 100.4. what should i do?

Depends : Would depend a little on why ur taking cephalexin. If ir being treated for an infection and ur temp is lower than it has been u could check with ur physician who wrote for the Cephalexin but he likely will tell u to watch it. If u have had a normal temp and it is getting worse (the temp is increasing more than 100.4 they would likely want u to follow up with them.