A facet injection is a minimally invasive procedure that can temporarily relieve neck or back pain caused by inflamed facet joints. The cause of facet joint pain (arthritis, injury, degeneration) is not well understood and can be similar in nature to disc pain. facet injection is a minimally invasive procedure that can temporarily relieve neck or back pain caused by inflamed facet joints. The cause of facet joint pain (arthritis, injury, degeneration) is not well understood and can be similar in nature to disc pain.