Leaving the roof of a blister intact is ideal, but may be impossible in a boot. Prevent, and if needed, pop and protect a blister to avoid infection.
If you recognize and respond to dehydration in outdoor adventure early, you avoid the many problems that follow from ignoring it.
If you are unfortunate enough to get hypothermia in the middle of nowhere, you probably lack the resources and time needed to fix it. Prevention is Key.
Take a Wilderness First Aid class because outdoor adventure entails risk, whether alone or with others, you may be the only person prepared for an emergency.