Apple Pencil warranty

The Apple Pencil Tip is a user-replaceable consumable item - that should be changed as soon as visible wear is evident. Unless materially defective, tip replacement is not a warranty item.

OEM replacement Pencil Tips are available in packs of four:

• Apple Pencil Tips - 4 pack

https://store.apple.com/uk/xc/product/MLUN2ZM/A

It'd be covered only if the damage is determined to be a manfacturing defect.