Hello, sahil0076!
Thank you for using the Apple Support Communities! I understand that you’ve been experiencing an issue with your iPhone X not powering on at first, and now you’re seeing blue, green, and red spots on the screen. I can relate to not having my iPhone work as expected and having to work through troubleshooting, so I’m happy to help you with the next steps on yours.
It’s possible that you’re experiencing a hardware issue with your iPhone. The next step is to have it inspected by one of our Apple-certified technicians. You can get support by phone or chat, set up a repair, or make a Genius Bar reservation for iPhone, iPad, Mac, and more here:
Contact Apple Support
Warmly!