Hi,
I'm not sure whether you are experiencing what I have lately, I have had a skin prob which is getting a lot better but recently my skin feels like it stings not terribly but uncomfortably so. It is dry and whatever I put on it and however often it doesn't seem to make a difference.
Is your skin dry too? If not, is it possible you have come in contact with something you're allergic too. Some people get a reaction to their own sweat, but I would imagine that would be more all over..
best wishes
hope its not the exercise

M.B.x