Can u die from a pilonidal cyst?

Not likely: But if the infection is caused by invasive bacteria such as mrsa, it is possible. Seemingly trivial infections can turn into a life-threatening condition if not treated properly. See a surgeon for an opinion.

Sepsis: Very unlikely to ever happen. But it can. Any source of bacteremia (bacteria getting into your blood stream) can turn into a serious condition called sepsis. Pilonidal cysts can do that, decubital ulcers can do that (superman christopher reeves ultimately passed from complications related to bacterial skin infection and sepsis).