If the 4mm lung nodules are caused by infection, there is a possibility of self-healing, while if they are caused by malignant tumors, they usually cannot be self-healed. 1. Infectious lung nodules: For 4mm nodules caused by infectious diseases, if the condition is mild and the symptoms are not serious, then there is a possibility of self-healing, patients do not need to carry out special treatment, regular follow-up observation can be. 2. Malignant tumor lung nodules: for malignant tumors caused by lung 4mm nodules, due to the high degree of malignancy, often can not be self-healing, can only be improved through surgical treatment to reduce symptoms and prolong the survival period. The commonly used surgical methods for lung nodules caused by malignant tumors include thoracoscopic surgery and open thoracic surgery. Lung nodules can be caused by malignant tumors, infections and other factors, regardless of the cause, patients need to attach great importance to the early medical improvement of relevant examinations and timely treatment.