As hematomas break down and absorb the firm collection of blood, they eventually change to yellow or brown. Hematomas can become quite large and collect enough blood to cause low blood pressure and shock.

Why would a hematoma grow?

If there is great pressure within the blood vessel, for example, a major artery, the blood will continue to leak through the damaged wall and the hematoma will expand.

Can a hematoma change size?

A large hematoma may last weeks to months and as it heals it will change color and slowly shrink in size. Hematoma pain and swelling may be treated with over-the-counter (OTC) pain medications.