My main issue here is that, despite being technically written fine, you don't actually have any interest until a bit over the halfway point, when SCP-999 finally is introduced. You have imagery about the moon and the forest that means nothing because there is no undercurrent of interest throughout the story. The main character is someone who spreads a lot of goodwill, and as a younger person, they went to go commit suicide before seeing it, but that's not like, enough to generate interest in me. You don't need something so fantastical or overblown, but there's nothing to really go on. I think you need to rework the structure of this story, or its flow, in a way where you grab my attention from the get-go. On this site, that's incredibly important; hooking the reader from the first paragraph on. I don't really have too much advice on this part. I think it might be worth considering examining the longer-lasting impact of 999 though. After all, even if its effects are long-lasting, it just tickles people. So why did this person feel as if their worries went away? How did they internalize it? How did they reflect upon this throughout life?
Your main character also has to be interesting, not just the scenario you give us. If you can do that, I think you can make this work. After all, the world is fantastical, even in its most mundane situations. 999 is the embodiment of that I feel, but what makes it fantastical as opposed to just anomalous? Why is our main character someone who we feel is worth observing through their eyes? Why do they do what they do? Again you don't need to make a long tale, but I feel as if this stuff is worth addressing to some degree.
