SCAB

noun

1. An incrustation over a sore, wound, vesicle, or pustule, formed during healing.
2. The scabies.
3. The mange, especially when it appears on sheep.

verb

1. To become covered by a scab or scabs.
2. To form into scabs and be shed, as damaged or diseased skin.
3. To remove part of a surface (from).