Can ringworm spread? Which cream should I buy? When should I know to see the doctor vs topical creams?

Oh yes, unfortunately, yes. It can spread to other parts of your body (including the feet, nails, scalp, or beard). Ringworm can also spread by contact with objects or surfaces that an infected person has recently touched. I reckon you should go see a doctor as soon as you can if you suspect you have ringworm. You'll never know when and who you can spread the ringworm to.