Will lenovo give me a new laptop via warranty?

I got my laptop in August, and I noticed dust getting caught in the keys so I popped the keys out but one key came out with the retainer and I tried to shove it back in and some of the pins holding the retainer got bent.

I managed to straighten the pins and put the key and the retainer back and it still works but feels a bit clunky.

Can I get a new laptop from lenovo?

No chance. They don't send new laptops, ever. They will replace the parts on broken ones (i.e. The keyboard is replaceable).

Since you're the one that broke it (it will be clear it's not a defect), chances are they will charge you, as well.