Dude Henkaku isn't permanent, and needs to be installed every time the Vita is turned on.
Go here
https://henkaku.xyz/ on your Vita and install it again.
You need to relax and read if you want help.
1). Hold down the power button on the vita, and tap "Power off".
2). Turn the Vita back on.
3). Open your web browser on the Vita, and tap the bubble in the bottom right corner.
4). Clear cache, and browsing history.
5). Visit
https://henkaku.xyz/ and install the exploit again.
Henkaku is like the temporary HEN for PSP, hence it's name. It had to be ran EVERY TIME the device is shut off.