Chafing More Condition_symptoms My Friend Has A Dry, Chafing Rash On His Inner Thigh, Any Thoughts As To What It Is?

My friend has a dry, chafing rash on his inner thigh, any thoughts as to what it is? - chafing more condition_symptoms

Athletes who have recently learned for the first time, but he is very athletic and was treated with antibiotics, highly ridiculous. It is almost painful for the health and can not understand what is behind. It is located in the folds of her inner thighs, near her sex. The rash looks more friction, without the red bumps, but is extremely painful. Any thoughts or ideas would be welcome! Thank you!