Does ringworm have any long term affects?

Not particulary. You may have an enlarging rash and itching but "long term"? Just don't put up with it long term! not all "ring worm" is ring worm. If you have one, treat it with otc terbenifine (lamisil) for a minimum of 2 weeks. If persistent or unsure, see your pcp or dermatologist for further evaluation and treatment.
No. Common but not harmful easily treated problems are abdominal pain sleepless due to itching and restlessness.