Hi Autumn
Did the scale weight increase the day after your full body workout and this is the only change in your routine including the type of food you took in?
I only ask this because there are a lot of reasons why you may be retaining water. Because of this I really can't say when the retention will drop. However, if it is due to lifting you may notice a slight increase the day after a really demanding workout (one in which you feel DOMS, delayed onset of muscle soreness, or it hurts so bad I can't squat to use the bathroom) That kind of sore will often lead to some retention.
Usually, I do retain water after leg day. It's just a given especially if its a new routine. However, keep in mind there are other reasons for water retention:
High sodium content in meals
Higher carb intake the previous day or two
Maybe a higher carb intake the evening before (usually I don't eat after 7:00pm but if I do and it's a carb...I'm going to see a "gain" of about 1.5lbs
Hormonal fluctuations and menstrual cycle will also show a slight gain.
Lack of adequate intake of water the previous few days.
These are just off the top of my head, I'm sure others could add more reasons. Just wanted to have you consider all the possibilities of water retention and not just from strength training.
Likewise, a slight loss followed by a slight gain could also be where you were dehydrated at a previous weighing and rehydrated the next. Seriously, half pound to one and half pound fluctuations happen all the time. We must look at the overall downward trend over a period of several weeks..
It would be more harmful if you become frustrated by the slight gain you see from lifting and choose not to do strength training. It takes time but it will occur.
You've probably already know the scale doesn't show the whole picture...I think the best indicators of our progress are the clothes that hang in our closet...pull out something that is just a size to small and keep trying it on every few weeks.
If you are taking in enough water, eating to fuel your workouts and doing your best inside the gym the results will appear in your clothing probably before they will on a scale.