Hello. Thanks for writing to us at healthcaremagic I think you most probably have sebaceous cyst. Masturbation has no role whatsoever in its causation. A sebaceous cyst, as the name suggests is an accumulation of thick, chessy, foul smelling content which is derived from the sebaceous glandular secretions lining the cyst wall. These contents may come out or may be expressed through a small opening or punctum. The cyst has a tendency to refill if it is not removed in its entirety along with the cyst wall, therefore, the recurrence. I will suggest that you visit a dermatologist in your region for a confirmatory diagnosis. A sebaceous cyst needs to be removed surgically. Regards