Took cephalexin to treat painful lump in armpit. it went away temporarily but came back. what should i do now?

See your Dr.: This suggests that cephalexin helped but some of the bacteria causing the lump survived and the infection was not fully eliminated.There are 2 possible reasons-you needed to take a longer course or some of the bacteria became resistant.If I was treating you I'd prescribe a different antibiotic for a longer time but you should see the Dr. who prescribed this (or someone else) for further treatment.