Petroleum jelly medical grade is used all over the world to protect and heal dry skin, from dry, cracked hands to hard skin on heels, as well as for beauty purposes, like softening the lips or highlighting the cheekbones . Vaseline is used to protect and repair the skin. Vaseline is used for preventing diaper rash, but it can also be used to protect minor cuts and burns, to soften skin, and to lock in moisture in dry, cracked skin.