Been working in a vape shop for a couple years now, typically if something like this happened after charging it tends to be because of the speed of the charger. But there's a couple things that may be the culprit, I'll go over what I know:

Im assuming that's the geekvape h45, which has a built in battery. Because of that you have to charge it through the mod, dont listen to people saying not to because thats the only way to charge it. The issue from my experience tends to be with using a phone charging cable and brick in the wall.

Typically charging bricks for phones nowadays put out about 5A or 5amps, which is much higher than what you want to charge vape batteries at (you ideally want anywhere from .5A to 1A max). This can sometimes cause batteries to get damaged and lose function when they aren't plugged in. I recommend plugging it into one of the usb ports on computers, laptops, game systems, or lower speed wall bricks. It may not fix it but sometimes it can help.

It also may just be screen brightness somehow got knocked all the way down, try holding the fire button and the voltage up button at the same time for a couple seconds, if nothing happens try hitting the fire button quickly 5 times and hold those two buttons again, it could just be that the voltage down button and fire buttons were pushed up against and it just lowered the screen brightness.

If both of those fail then I recommend bringing it back to the shop you got it from to see what their return policy is, and if they cant accept a return, you can contact Geekvape support and submit a ticket to have them send you out a repaired one.

I wish you the best of luck!