The best I can offer is Dust & Scratches filter at 15/6. That will get rid of the strongest hair, but plausibly leave the lighter hair remaining.
By not overexposing it. Go back to raw if necessary.
By the way, read "The Photoshop Method" (second section) on this page. It's written to be used with my web watermarking action, but applies generally in your case too.
Nothing at all. Relax.
What about if you check the Image Size immediately after cropping, before saving or closing or reopening?
By the way, I strongly suggest clicking on the little cog in the Options Bar, and choosing "Use Classic Mode".
This is difficult for me to address, because I can't really tell which part of the process you don't understand.
Do you know how to add a drop shadow via the "Fx" button in the layers panel?
I don't even think cloning will work, to be honest. You'd need to do a lip swap from another photo, if possible.
Or embark on some very painstaking lip creation.
Or simply accept that the bubbles are freakin' gorgeous, and leave them.
You've got the layer thumbnail selected, rather than the mask thumbnail. Click on the mask thumbnail in the Layers Panel, so that it has the little border around it.