Terran it up....ehhh

[Samszym]

Glad I could help dude! The lighting's looking a lot better now too.

I don't believe come across that problem before! How are you resizing exactly? My first thought would be you need to work more zoomed out so you see what the full picture looks like as you're working on it. Buuuut maybe you're already doing that.
If the resized image is actually sharper than the zoomed out full-resolution version then your copy of photoshop is probably demon-possessed. Exorcisms are expensive so an alternative solution would be to zoom out so you can see the whole piece, turn on photoshop's full window setting, then take a screen-cap and save it as an image.

Good luck figuring that issue out!