How do i get it back? 
Well, ctrl+z is a good option, but if you’ve done stuff after deleting your character you’d have to make it again. For how to set up a first person character, check out UE4 Tutorial - Create a Movable Player Character From Scratch - YouTube
or use google, as there are lots of videos and stuff showing how to make a first person character from scratch.
Another option is opening a new firstperson template level, copying over the .uasset file of the firstpersoncharacter and then it should work?
If you’re lucky enough, you can find it back in your project folder: …\Saved\Backup
Here stores UE4 back-ups of edited assets, but i do not know its exact criteria of when it decides to store a back-up of a file.