In one study published in JAMA Open Network, researchers found that 87% of the preliminary diagnoses made during telemedicine appointments were later confirmed during in-person appointments.
To put it simply: diagnoses over video are usually spot on.

December 2, 2022 – Researchers evaluated more than 97,000 video visits across Mayo Clinic between March and June 2020. Of those visits, 2,400 patients had a visit for a new health concern and followed up with an in-person appointment within 90 days.
The highest rate of matching telemedicine and in-person diagnoses was found in specialties that included psychiatry and psychology, allergy and immunology, orthopedics, and urology. While diagnostic concordance was slightly lower in specialties such as dermatology and ear, nose and throat (ENT), still, close to 80% of those diagnoses were confirmed in person.