Rather than using the lasso tool try this..
Duplicate the background layer twice (so that you have an original to fall back on should you need).
With the top layer selected in the pallet, press the "add layer mask" button. A white box linked by a chain to the thumbnail in the selection should appear.
You can click on the two boxes in the layer to select the actual image or the layer mask. With the layer mask selected, select the Brush Tool (keyboard shortcut B) and now you can paint black on the mask to make a virtual hole through the layer, if you use white it mends the hole.
It can help if you turn off visibility for the underlying layers to see what you're doing.
You can use a soft brush to act like the feathering you applied with the lasso selection.
Once this is complete you can do all the adjustments you want to the layer just below the one with the active mask and it will only effect the area you painted on the mask.
Whats great about the mask is that you can deactivate it and the top layer will be completely unharmed as well.
Once you're finished you can either merge all the layers or you can make the ones you want to merge visible and choose "merge visible". I often do this to keep a copy of the original background image. I can then repeat the mask operation on another area of the image if i want.
Once you get really advanced and comfortable with this you can have multiple masks in different areas of the image over lots of different layers. It's hard to get your head around at first though!
This has turned into a bit of a tutorial!
