Wearing gloves helps avoid them, of course. Foot and toe blisters from ill-fitting shoes are the most prone to complications. Moleskin can help prevent blisters on areas prone to rubbing, such as the heel. The skin will regrow from underneath. The loose skin is dead.
Blisters can occur from heat, frostbite, chemical injury, or friction.
Unless infection occurs, blisters usually heal quickly. Broken friction blister on the palm. In general, a friction blister is most comfortable if you leave skin intact over it. If the blister is uncomfortably tight, or if its location means it will have pressure on it as you work, you may need to let the fluid out. Typical biker's handlebar blister at the base of the thumb, facing the index finger.