To heal is to recover or become healthy again. You'll need to wait until your blisters heal before you put your hiking boots back on and climb Mt. Everest.
They say time can heal, or cure, a broken heart, while you can be sure that rest, an ice pack, and propping your foot up will heal your twisted ankle. The Proto-Germanic word khailaz, which means "to make whole" is the root of both heal and the closely related word health. Don't confuse heal with heel, which is the back part of your foot or the command that makes a dog stop.