If you have a wound on your foot, you can go out with a coin to protect it.

Chapter 301 Section 29

You cannot wear a completely folded article of clothing on your shoulders. If it is worn normally over most of your body and folded up a little, it is permissible to wear it that way on Shabbos.

Chapter 301 Section 30

If the normal way the wear a particular article of clothing during the week is to have it folded completely on your shoulder, it is permissible to wear it that way outside on Shabbos.