Mom has a huge infection in her toe-podiatrist gave 7 day rx antibiotic. no improvement at all by day 7. she now has fever. call dr. or er?

Yes: If there is no no improvement after 2-3 days, patients can call their doctors for help. Seven days with a "huge infection" doesn't sound good. In such a situation, if the doctor cannot examine the toe right away, one can go to the ER to get examined. An infection that doesn't improve with oral antibiotics may need IV antibiotics in the hospital, unless it's just a minor infection.