Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Contact a clinician sooner if there are open sores, significant blisters, drainage, or signs of bacterial infection.
People with diabetes, poor circulation, reduced foot sensation, or a weakened immune system should seek individualized advice about new foot rashes or skin breaks.
Arrange routine follow-up with a clinician if the rash does not improve after a full course of nonprescription treatment, repeatedly returns, spreads to the nails or other body areas, or becomes painful.
An examination or skin test may show that another condition is causing the symptoms.
The article also says
Mild athlete's foot should begin to improve with correctly used antifungal treatment, although scaling and damaged skin may take time to heal.
Check the product label for the expected treatment period.
After the infection clears, continue practical moisture-control measures.
Keep shared footwear and towels separate, change sweaty socks, and allow shoes to dry.
Treating a confirmed fungal nail infection may also reduce recurrence.
Every sign above is quoted from the sofidex article on Athlete's foot. If you are not sure, err upward — it is always reasonable to be checked.