I have a friend who has an itchy rash on his chest that develop into sores and eventually break and ooze. they are small and are all over his chest.

???????????: Is it only on one side of the chest or does it cross the middle ? Does it start as blisters, bumps, flat, red raised ,etc.? The causes of a rash can be quite extensive & diagnosis is often visual. A detailed description can help, but with this vague description I would suggest you have someone evaluate it. Treatment if needed would depend on what it is.