The way memory works in the brain is heavily state dependent. That means that your recall and recognition of past ideas/events is based on how you feel, what you are wearing, mental state, drunkenness, drugged/not, sleepiness, and pretty much any other state of being you can think of. The closer you are to the state that you were when you learned or experienced something, the easier it will be to recall.

This doesn't un-do the depreciation in memory you get from drinking, or anything else. Getting black out drunk wont help you get your blackout memories back, you'll just forget what you were trying to do.