Should you leave cuts and scrapes uncovered?

Yes you should leave cuts and scrapes uncovered, unless they are serious which can cause infection. The wind helps to heal them if you cover them they will stay moist and juice, you can also try putting some B.N.T powder on them so they will stay dry

You should bandage them until they build their own protective scab. After that the scab is the bandage and will dry out and fall off when fully healed.