I don't have a video about it, sorry, but you'll find some on YouTube, I imagine.
It's very simple, just circle the area (with a little bit of buffer around it) then drag the area onto another area of similar texture.
This looks like fairly standard file corruption. Just save them again from your master files, and send them to her again. I'd be surprised if it happened twice.
So if you wanted to do a black-and-white of this one, use Channel Mixer for your conversion. Add the Channel Mixer layer, check the "Monochrome" box, then enter 0%, +100%, 0%, 0% for the four sliders.
Download the PSD file
I began by duplicating the Background layer and doing the Liquifying on it. Then I added the mask and masked it on.
Then I realised I needed some new shadowing, so I created the Hue/Sat layer below the Liquify layer for that purpose.
Finally, I realised that some grass was crooked, so I added the Clone layer for that purpose.
If some or all of that doesn't make sense, add The Layers & Masks Class to your list.
Ok, then this is going to be challenging for you.
You'll find plenty of YouTube videos to teach you; I've recorded one here.
Give me a minute and I'll upload the PSD file of my edit, I hope you'll be able to make some sense of it.
Ok, I've got a fix to show you for your consideration. Let me know when you've fixed the colour space problem, and we'll go ahead and start discussing her skirt.