Greetings hrithikpurwar,
We understand that you have observed a discoloration on the trackpad of your Mac and are happy to offer additional information on this matter.
Our first recommendation would be to follow How to clean your Apple products under the section for notebook computers to see if it is possible to correct that observed issue.
We also want to let you know per Apple One (1) Year Limited Warranty, "This Warranty does not apply: (a) to protective coatings that are designed to diminish over time or batteries, unless failure has occurred due to a defect in materials or workmanship; (b) to cosmetic damage, including but not limited to scratches, dents and broken plastic on ports unless failure has occurred due to a defect in materials or workmanship..." and as such if this is a cosmetic matter, may not be covered under your warranty. You are welcome to seek assessment at an Apple Authorized Service Provider shown at Find Locations to have your Mac professionally examined and options reviewed.
We hope this helps!