If the skin is red and painful, the local pressure is hard, and a raised swelling can be felt at the site of the skin lesion, with a clear border with the surrounding area, elasticity and good mobility, consider it to be a subcutaneous cyst with secondary infection, and under the guidance of a doctor, carry out targeted treatment such as antimicrobial treatment or removal of the cyst; however, if the border between the swelling and the skin is not clear when the skin is red and swollen to the touch, the swelling does not move when pushed, and the mobility is poor, and tumourous diseases cannot be ruled out, histopathological examination is feasible to clarify the diagnosis early.