Im a field tech-I injuried my thumb falling in this apt complex stairwell?

there are four steps, (walking upward) three are marked yellow- the last step just blends in the walkway-(you cant see it) expecting to began walking, I trip on the last step fall foward in the push-up position, resulting all pressure on my left thumb severly injuring it- unable to work for a least 3months........can I hold this apt complex responsible for loss wages, & probably ending my career. Please help