The main reason for the arm being pinched and bruised is that the capillaries under the skin rupture and bleeding is caused. You can choose hot and cold compresses, applying ointment and other ways to deal with it. 1. hot and cold compresses: when the bruise just appeared, you can use ice towels for local cold compresses or ice packs, can play a stop bleeding, promote the effect of vasoconstriction. 24 hours after the change to local hot compresses, can accelerate the absorption of the local bruises. Hot and cold compresses are recommended under the guidance of a doctor to avoid freezing the skin because of the temperature is too low, too high scalding the skin. 2. Apply ointment: you can follow the doctor’s instructions for external use of safflower oil and other drugs, can accelerate the blood circulation in the affected area, promote the absorption of bruises and swelling; the use of compound heparin sodium cream class of drugs, can play a role in promoting the local soft tissue to accelerate the repair of the effect, the use of heparin sodium cream, can be used to promote the local soft tissue to accelerate the repair of the effect. If the arm is pinched and bruised, if the bruise has not subsided or has expanded, it is recommended to consult a doctor in time, improve the relevant examination, clarify the cause of the disease, and carry out professional treatment under the guidance of the doctor.