When You Pop A Pimple And Blood Comes Out. Palep explains that it is called serosanguinous fluid. It is possible that your pimple is affected by bacteria and the liquid fluid coming out of it is just the bacteria breakdown.

Shutterstock Though it sounds too weird to be real dermatologists advise patients to never pop a pimple in the so-called danger triangle This is the area that extends from the corners of your mouth to the bridge of your nose. But other times it will pop under the skin. In that case you probably had yourself a cyst.
But other times it will pop under the skin.
No when blood comes out it means the puss of the pimple is out. If blood comes out of a pimple this means that you have popped it and now it is healing and scabbing over. The presence of white blood cells in the fluid is a sign that they were fighting with the bacteria and during that process the pimple popped. Zeichner says this is nothing to be concerned about as blood will usually drain out of.