Hair transplantation is a treatment technology to repair hair loss, the technology is now more mature, but the following side effects may occur after hair transplantation: 1, bleeding: hair transplantation surgery requires an incision in the patient’s head, the incision may bleed during the recovery period, which is normal, but if the incision is abnormally red, swollen or bleeding, you need to contact the doctor for follow-up treatment; 2, infection. If you choose an irregular and unqualified institution plus improper operation of the operator, it will greatly increase the risk of infection. In addition, if the patient himself suffers from folliculitis, acne and other diseases of the head, it may lead to infection. If there is infection in the operation area, you need to go to a regular hospital in time for relevant treatment under the diagnosis of a professional doctor; 3. scar: for patients who choose the fut method of hair transplantation, a thin scar will be left after the wound suture of the scalp strip is cut, but it is generally invisible with hair cover; for patients who choose the fue method of hair transplantation, a white dotted scar will be left after the operation. If the patient is a keloid, it is recommended to avoid such invasive operation; 4. Granuloma: Since hair is a foreign body, if the hair follicle is not handled properly, it is easy to produce local granuloma-like reaction, but it can be removed by laser after the operation; 5. Superficial sensory nerve damage: Since hair transplantation needs to punch holes in the donor area and the recipient area, it can cause superficial sensory nerve damage, which is manifested as head discomfort. However, this kind of damage can be repaired by the body itself after about six months to a year, and the symptoms can be relieved.