[@Haeo]

Alright let's go down this list then.

First off while fire can be trapped and used in a bottle or magical some that doesn't allow it the ability to convert into your own life energy. Your body is simply to complex for that to work. If you wanted to feel warm sure but restoring life isn't something a normal fire can do.
Next while that is possible you would need to extensively study what is powering you as an individual. Your a complex organism and as such you would need to learn about your physiology and hope it works before you can attempt to transfer a piece of your own life power for another.
Again referring to the first one fire can be trapped and used in magical stones but you would need to study your own physical makeup for that to work. You can't simply cut off a finger and expect it to burst into flames after all