Go to the doc, do what they tell you. Then shower every night immediately after practice. There is all kinds of debate as to what is the best soap and what to use or not use, many will say just shower. Prevention is key. Keep your mats clean. We make sure that wrestlers with ringworm are covered or don't wrestle if they can't cover the ring worm until the ring worm is no longer contagious. There are also a number of good products available to cover up with before you wrestle. This time of year I get on to my son so much he can't stand it to make sure that before every tournament and every practice he puts on a product called 99 from head to toe. It costs about $10 and will last the duration of the year.

Links:

http://dermatology.about.com/cs/fungalinfections/a/ringworm.htm

http://www.astdhpphe.org/infect/ringworm.html