Do I need to reprogram or aim this after installation?

No reprogramming needed—this is a passive assembly. You may want to check headlight aim after install to ensure proper beam pattern, especially if your old unit was misaligned.

Does this come with the bulb?

The assembly itself is included; bulb is not. You'll reuse your existing bulb or source a replacement separately if needed.

Will this work if my other headlight is aftermarket or damaged?

Yes. This assembly is a direct replacement for the left side and doesn't depend on what's on the right. Just make sure both units are aimed correctly so your beam pattern is balanced.