Hematoma after surgery or postoperative hematoma is basically a localized collection of blood at the surgery site. It is defined as the collection or pooling of blood under the skin, in body tissues or an organ. Hematoma is a common potential post-surgery complication, and is commonly seen after a face-lift surgery.ematoma after Surgery. Hematoma is a sac of blood that gets accumulated at a surgical site, after surgery. This accumulation of blood leads to pain, inflammation, and discoloration of the skin around the surgical wound.