My son who is 15 has some open oozing sores on his arm around his elbow. A little over a week ago is started as a tiny blister. progressively is has grown to about the size of a nickel. Now there is tow of them and they appear to be spreading. They are dry in the morning (left uncovered at night) and at night they seem to be oozing more. He plays lacrosse and wears all the appropriate gear including elbow guards. The sores seem to be spreading even since he hasn't had the guards on for a few days.