Doctors please help!!

So I am just gonna get to the point. The skin on the end of my nipple is peeling off and it is really painful. Why is this happening and does anyone have any idea what I can do to stop the pain. It tends to hurt most when I get out the shower or bath and wrap a towel around me and it brushes agains it or if I run and my bra rubs agains it. Thank you xox