This is Prurigo nodularis. Its a skin condition in which hard crusty lumps form on the skin that itches intensely. This may itch constantly, mostly at night, or only when a light brush of clothing sets off a round of severe itch. It may b  itching and  only ends when it is scratched to the point of bleeding or pain. Medicatio is available for the same. And it can b controlled. Consult a Dermatologist for the same to prevent further progression of the lesions.