I have blood pockets all over my head. what can cause this?

Trichilemmal Cysts: Trichilemmal or pilar cysts are common intradermal or subcutaneous cysts, occurring in 5-10% of the population.Greater than 90% occur on the scalp, where trichilemmal cysts are the most common cutaneous cyst. Trichilemmal cysts are almost always benign. They may be sporadic or they may be autosomal dominantly inherited. Surgery is the only cure.