Blisters are going to happen as you are getting ready for an event like Selection or Kokoro. They may even happen during the event and even if your feet are hard as stones, you need to be prepared to fix them.
In making my kit I continued to think that I was making it so I could help out a team mate because I don't like thinking negatively. Either way, I will be prepared.
You don't need much to be able to prevent blisters or continue on after some have formed. My kit fits inside an Altoids box.
The contents are:
Leatherman Micra with scissors
Duct tape wrapped on a pencil
This stuff easily fits in an Altoids can and can be waterproofed by putting that in a snack sized ziplock.
The whole kit can easily be put in your shirt pocket or in any backpack.
This stuff is what I need, but you may need more or less. The important thing is to have some sort of a kit that you can use to take care of yourself or a team mate. It could be the difference in finishing or not or in extreme cases, life or death.