Hi Wallaby, you can go to any doctor of your choice and they will write you a perscription which you then take to the Apotheke or the International Apotheke at the
Hauptbahnhof (Main Station) they will speak English too. Any Apotheke will do really; If they do not have the medicine there, they can order it and you can pick it up usually within 12 hours. Have you tried natural medicine - Homeopathy. Taking pills may help your hair problem but in the long run may not be good on the other internal organs; stomach lining, lver etc. or other other side effects.
You will be charged a small fee of about 4 Euros for the medicine at the Apotheke. The Doctor is free as long as he takes patients who are members of a Health Insurance (Krankenkasse) in your case the AOK. Well almost free; a new charge of 10 Euros per Quarter has been introduced recently - to cover administration costs. Some doctors just take private patients only. There are some Homeopaths who are private only and you would have to pay for the consultation too.
Anyway, I hope it works out for you.
Cheers
Mary