Making a medical diagnosis based on the sparse information people post here is very nearly impossible. What you may not realize is that there is alot more to diagnosing than you think. Some of the causes of numbness in the feet include but are not limited to Diabetes, Hypothyroidism, Vitamin B-12 deficiency, Rheumatoid arthritis, Pernicious anemia
Peripheral neuropathy, trauma such as ill fitting shoes, injury, low back problems, pinched nerves ...
Having said all that, your advice to your daughter seems to make good sense. It is possible that her shoes may have injured the superficial nerves in the foot. If they are only slightly injured, it may take several weeks-months to recover. This is not an absolute. Nothing in medicne is.