Fibrosis or striae in the lung, this is a residual infection in the lung that has not been absorbed, it will remain some shadow in the lung, after a long time, due to its fibrosis will become striae, sometimes there will be some nodules, or some mesh structure, and even honeycomb structure. Many people say that I had pneumonia once, but there was no sputum at all at that time, but this is not a good phenomenon, because the lung is the method of excretion of sputum, so that the inflammation in the lung can completely disappear. If there is no sputum excretion and the body absorbs it back, it will be too late and the lesions will remain if the absorption is not complete, so once there is an infection in the lung, use as much sputum-forming medicine as possible to get it out. This kind of solitary cords is usually not a big problem, but once the reticular structure or honeycomb shadow appears, it is very damaging to the lung, and it will continue to be infected in this place, so it needs to be paid attention to.