[mothered]

I was attempting to SE a lenovo laptop

Is It through Lenovo or otherwise?

I have managed to get a label to send in the laptop for repair. I claimed that the battery was swollen.
What can I do now?

Tell them you were ready to organize the return, but decided to turn It on - just to see If It functions as per Its original state. And If It did, you would've kept It. This gives them some reassurance of a caring consumer who's not targeting a warranty claim unless It's necessary.

However, It started smoking, hence you threw It out for health and safety concerns.