It's 1364. Poor Harry has a boil on his face. He is really upset and has been hiding from the public for days. He is quite wealth though, which means he can afford to be treated.
Harry visits a physician, to get a diagnosis for his wound. The physician takes a sample of his urine and consults with his astrological charts, before giving Harry a diagnosis and giving him a course of treatment. (The physician wouldn't actually give treatment himself.)
Next, Harry visits an apothecary. The apothecary mixes his prescribed herbal remedies together, and treats him. Apothecaries didn't have as much knowledge or skill as physicians, they just mixed the herbal remedies that physicians prescribed, and gave them to the patient
Finally, Harry visits a barber surgeon. Barber surgeons were usually not very well qualified, but they had the right tools at hand, so they performed small surgeries quite well. The barber surgeon uses a sharp knife to remove Harry's boil, after Harry's herbal remedies hadn't made a difference.
After visiting a physician, apothecary and a barber surgeon, Harry's boil has finally been treated. He is now much happier and he isn't worried about showing his face in public anymore.
Harry is now back at home and he is much happier than he was before.