Hi, welcome to the forum, and thanks for including photos.
I think your problem is very likely due to the quality of your soldering. (Don’t worry, we’ve all been there.) I would start by trimming back any protruding wires and component leads. They could be causing a short, especially in a mini pedal where things are packed in tightly. I would also advise reflowing your solder joints to get rid of any blobs and to fill in eyelets that have not been completely filled with solder.
For some inspiration and helpful photos, find the stickied post “Stephen’s Tips for a Successful Build.” Not everything in that post will apply to your build, but it is extremely helpful for knowing what good solder joints and wire dressing look like.
Let us know if we can be of further help, and keep us posted on your progress.
Edits: now that I'm on my main computer, here are helpful links:
Stephen's Tips For A Successful BuildAbout reflowing solder