Hello, I can understand your concern for the ringworm infection on arm. After analyzing your query with diligence it appears to be more of problem due to scratching the area rather than ring worm itslef. Most of your symptoms indicate an infection at the affected site. In your kind of cases I generally prescribe a course of antibiotic along with a cream containing antifungals such as clotrimazole or miconazole. An antihistamine is a must to reduce the intensity of itching. I suggest you to meet a doctor to get proper treatment.