Can this be fixed?

[Allurapre]

I tried the ctrl + f1 but it didn't do anything

[LadyWYT]

Have you tried exiting the world and reloading it? Or even rebooting the game entirely? And are you running any mods? I think I had issues with chunks sometimes loading incorrectly/being very slow to load when I was running several mods at once(likely more mods than what was ideal for my hardware at the time). If that doesn't fix it, however, and you are running mods, then I would suspect there might be incompatibilities between mods, or a buggy bit of code that's unfortunately corrupting the world. The former might be able to be fixed by figuring out which mod is causing the issue, and removing it if possible(although this could always cause other issues depending on the mod). The latter can't really be fixed without an update to the mod itself.

If you're not playing with mods though, and the chunk still isn't loading despite a reboot, then it may be an unfortunate bug, or possible world corruption somehow. In that case I'm not sure that there's much that can be done about it.

[Allurapre]

I have Better Ruins mod but I've had that for a bit and have no issues on other world gens. I ended up deleting the world because I believe it somehow became a corrupted save as when I returned to my spawn point it also suddenly had missing terrain. 

I know unexpected stuff can happen anytime in a game but this was my favorite world gen, I even renamed it Home Sweet Home and of course I didn't remember to write down the seed but perhaps I will find a better world gen in the future.

[LadyWYT]

1 hour ago, Allurapre said:

I even renamed it Home Sweet Home and of course I didn't remember to write down the seed but perhaps I will find a better world gen in the future.

Plus 1.20 is right around the corner, which would be an ideal time to start over fresh. Although for future reference, I do believe there is an option to copy existing world settings--that includes the seed as well as all the other adjustments you made when you first created the original. Useful if you find a world that you really like and want to keep around in some form or another.