Ringworm is a fungal infection, ringworm can be avoided by staying clean and dry. You can use bleach on a Qtip and apply a little to keep it controlled. They have good over the counter medicines that work well also.Lamisil is a common anti fungal cream used to get rid of ringworm.
Avoid scratching the ringworm. Keep it clean and use a special cream called Jock Itch. Apply daily for atleast 2 weeks. Put it on twice a day. You should be able to find it at your local drug store or pharmacy.