If light bends due to the curved spacetime,would not the act of bending light warp space? How does one describe curved light?
Light does curve spacetime. This is discussed in the question Does a photon exert a gravitational pull?.
In many cases we are describing the interaction of very massive bodies with much lighter ones, for example a satellite orbiting a planet. In these cases it's a good approximation to ignore the curvature of spacetime caused by the lighter body. The sort of situation you describe would be the lensing of light by a massive object, and when calculating the bending of the light we ignore its affect on the spacetime curvature. We do this because we expect the effect of the light to be unmeasurably small, and because trying to include the effect of the light makes the calculation vastly more complicated.