Makes your blood boil meaning

It is first necessary you understand that "blood boiling" is an actual process used to thicken blood for consumption as food or use in other processes.

When a person says something is making their blood boil, they are neither referencing the actual industrial process, or implying that it is actually happening in their body. They just mean that they are very angry. This form of writing is known as an idiom. Where a phrase is used to reference a condition not actually present, but the meaning is understood.

"Makes your blood boil" is also a hyperbole (an exaggeration). It means that you were angry and felt hot and agitated as if your blood were actually being boiled by your emotions. Again it is understood by listeners what the idiomatic intent of the hyperbole is.