Novel psoriasis body surface affected area BSA measuring instrument and measuring method

The invention discloses a novel psoriasis body surface affected area BSA measuring instrument and a measuring method, the novel psoriasis body surface affected area BSA measuring instrument comprises a host, a pen holder and a connecting wire, the host is connected with the pen holder through the connecting wire, and the novel psoriasis body surface affected area BSA measuring instrument further comprises a take-up bin arranged on the host; the winding column is rotationally arranged in the take-up bin, and a winding gap is formed between the outer wall of the winding column and the inner wall of the take-up bin; the guide block rotates synchronously with the winding column, is in threaded connection with the inner wall of the take-up bin, and is fixedly connected with one end of the connecting wire; and the first driving assembly is used for driving the winding column to rotate. Through the arrangement of the first driving assembly, when the instrument is not used, the winding column can be driven to rotate