Why do my eyes look worse after lower blepharoplasty than before?

The removal of what little fat you had in your lower eyelid has not helped you.  Unfortunately, the bleaching creams will do nothing.  Because you have an olive skin color, I do not recommend chemical peels.  They could hyper-pigment or hypo-pigment you.  You hare likely still swollen and this is not helping.  I would wait another month and then find an expert injector to perform under eye filler.  Sorry about the frustration.

I notice under eye hollowness, causing some shadow, dark circles. See an oculoplastic specialist for evaluation. Improvement is possible.

You are very hollow now low down on the lid, at the lid-cheek junction.  I am assuming fat was removed, and while this may eliminate the puffiness, it can create a hollow appearance post-op.  You will need to wait longer for all inflammation to subside, but will most likely need some fillers to restore the volume.  By adding volume you almost always improve the dark circles.