Layer mask showing on the outside when exported

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#1

what it looks like in photoshop:
image

Then this is what it looks like when exported:
Snow Frame

I used a layer mask and for some reason, you can see it on the outside when it’s saved to my files.

Does anyone know how to fix this?

#2

Just so you know, I didn’t use a watermark as I just made this to add onto a portfolio.