Could this be ringworm or another skin disease, and how to treat it? The nose developed thick crusting with discharge a few days after coming home

The image shows thick crusting on the nose, likely from fungal infection such as ringworm, a common skin disease that also causes hair loss beyond the nose.

Get a skin scraping at a vet for the cause and targeted treatment; if unavailable, clean the site and use antifungals, watching for improvement, and see a vet if none.