Hi fattyfattyboombooms – welcome.
Firstly, would it perhaps be possible to borrow the book from your local library? Even if you decide not to use any of the recipes therein, reading it will help you understand the science behind this way of eating, and give you lots of tips etc.
As far as loose skin is concerned, the faster you lose weight, the more of a problem this can become, as the elasticity in your skin has less time to adapt. But there are a couple of things you can do to help, number one being hydration – both inside and out – ie drink loads and loads of water, just plain good old tap water, and moisturise, moisturise, moisturise your skin from without. Exfoliation could help too, as it will improve blood circulation to the skin. The other thing which may help is to eat good protein – two necessary ingredients that keep skin plump and elastic are collagen and elastin. Protein-rich foods such as cottage cheese, milk, legumes, tofu, beans, seeds, nuts, and fish all contain collagen and elastin forming components, so eating these should help – though obviously you have to do this within your 800 calorie count.
Unless you lose literally mountains of weight, your skin should eventually shrink back a bit, (although the longer one has been carrying excess weight, the less likely it is to shrink back, and the older you are, the worse it will be as young skin is far more elastic than older skin) – maybe not completely, but at least better than it was, but it may take up to 2 years to do so.
Personally, I have never bothered weighing my veg, I just stick to the low carb ones (those that grow above ground – though not fruit) and eat as much of them, particularly salads and green leafy ones, as it takes for me to feel satisfied.
I am now on maintenance and this has worked for me, so hope it helps and good luck..