Screen cracked from vibration

I’ve had this tiny little chip (literally about 1mm on the top, no crack) on the back of my iPhone X for around 2 years, today I had it sitting on my lap and it made a funny noise when it vibrated, I picked it up only to see a huge crack All over the back of my phone, it hasn’t been dropped or anything it’s literally just cracked from vibrating on my lap, you can’t feel the crack so it seems internal, has anyone else had this issue? What can I do about it? In the photo you can barely see the chip I originally had in it it’s just at the start of the corner