My phone dropped and screen was striped unresponsive

Hey! Yesterday I dropped my phone and when I picked it up it was full of coloured vertical lines and I couldn’t see anything on display and it didn’t work, but audio was working.

I thought display was broken and I will need to replace it, but after time, lines were noticeably smaller and I could finally see something on my home screen and then after some time it was totally gone and the phone was 100% working.

What was happening? Do I need to care about it? Or just use it and don’t be bothered by it.

Thanks!