If your baby's delivery was difficult, a forceps may have been used to help him through the birth canal. The pressure of the forceps on the skin can leave bruises or scrapes or can even damage fat tissue anywhere on the head or face.
Fetal monitors can also cause scrapes and scabs on the scalp.
You will notice the bruises and scrapes 1 or 2 days after birth. They will disappear in 1 to 2 weeks. Injury to fat tissue injury won't be apparent until the fifth or sixth day after birth. A thickened lump of skin with an overlying scab is what you usually see. This may take 3 or 4 weeks to heal.