Well son...you've learned a valuble lesson.
Just an FYI, the "black headlights" on ebay have a small area on one reflector painted, and then the reflectors themselves do the rest. When the bulb is on, the reflectors do thier job.
Did you paint the reflective walls or the lens? If you painted over the chorme reflective walls with regular spray paint, wipping them carefulluy with a rag with some brakekleen on it will get most of it off.
If you painted the platic lenses it's easier. Try some 800 grit wet or dry sandpaper then 2000 grit, then polish with scratch-x. Lots of work, but your lenses will be clear. Then apply protectant to keep them that way.
I have some smoked headlight covers for sale if you really want to have something dark.