I think it's mostly just a screenshot tool but if you can help, heres my situation.

I took a screenshot using the app, uploaded it, but then ending up copying something else before I saved the first screenshot. Is there anyway to find it?
I can't find it in C:\Users\Username\Documents\Lightshot

Thank you for any help.

I use Lightshot myself but never using all it's features, etc. I just simply use it as take a s/s and share it directly or use the upload function you talk about.
There seem to be a few more features when i looked into FAQ's etc and i found this that might help your solution since you uploaded a s/s and then accidentally copied something else.
Hope it works

Thank you for that video n1ghtm4r3, Learned a few new things about it. According to that video, screenshots will only save if you're logged in to the app which unfortunately, I was not.
If anyone knows a different way of recovering a lost screenshot, I'm still looking for a way. Thank you.