It might be worth consulting a pharmacist. They usually have a lot of knowledge about these kind of things. Dermatologists are most likely running but at limited capacity meaning that the most acute and severe cases are seen quicker and if your problem isn'y urgent, there could be a long waiting list. In terms of appointments, it really depends on their policies. Our local hospital does face to face outpatient clinics, local GP does phone calls only and the Emergancy out of hours service does video calls only.
Hope this help a bit and that you feel better soon!