In Wolf Moon, Scott McCall had a large gash from Peter Hale's Bite. A day later, he took off the bandage, and saw the wound had healed completely with no mark or scaring visible. He'd been later pegged to a tree by an arrow, but after it was removed, the wound healed overnight. He also noted he no longer suffered from his lifelong asthma.

 

In Heart Monitor, Derek Hale was clawed through the back by Peter Hale, thrown against a wall and knocked unconscious. Because this wound came from an Alpha, Derek was out of commision for days.

 

Scott wasn't healing from a wound in Frayed, beacuse of somataphormises; he was feeling depressed and guilty over Derek's supposed death. After Allison stitched him up, he apparently healed after he "believed" it healed.

 

In Restraint, Erica Reyes was struck with kanima venom which disabled her healing, and she had an epileptic seizure. Similarly, in Required Reading, after Scott reads Valack's subliminally coded novel, it's effects meddle with his healing and his asthma psychosomatically returns.

 

Werewolves can subconsiously trigger their healing by causing themselves pain.

 

Like their senses and transformations werewolves can presumably develop control over their healing.

 

In Wolf's Bane, one half of Peter's face remained burned from his six-year coma due to the Hale fire. Once he recovered, it's hinted he consciously kept his face burned so to keep up the ruse he was comatose, and in Wolf's Bane he apparently healed his facial burns.

 

A werewolf's healing can be hindered, and subsequently they will excrete, or vomit up black coloured blood. This is possible were they to be poisoned by wolfsbane like Derek in Magic Bullet, or Cora Hale by mistletoe.

 

In Unleashed, Derek was impaled through the torso with a pipe for a long time, delaying with the healing process, causing him to vomit the black substance as well as it bleeding out through the wound.