What Causes Red Circles On Leg?

I have a red circle on my leg about the size of a quarter. I have it now for 4 weeks. I just started 1 week ago the treatment for ringworm. It doesn't itch or anything. It is still there. When i put the medicine it just turns more red. It doesn't go away. my doctor said that he thinks it is ringworm but did a test for lyme disease too. I didn't get the result yet but it certainly doesn't look like a tick bite. How long does it take for the ringworm to disappear? Thanks