The thing with bad habits is they can really affect your development later on down the line, if not sooner. This is because constant tension can cause issues with muscles, tendons, stress etc. Stuff that can really take you out of practice for a number of weeks or months if serious. Try not to see it so much as "I cant play fast anymore" but more "Im making positive development with the right technique". You might not be as fast, but the notes you play now may have more power and confidence, that could later on be sped up. I've been playing for 15 years now, and have recently decided to alter my picking technique for a more effective performance. It's taken me a number of weeks, but I know at the end I would have made the right decision for development purposes.
What you will find (or what I have found) is you often develop a few different picking styles in order to cater for certain styles or genres. For example, if you approached a John Petrucci lick with a funk rhythm technique, its not going to happen. And vice versa.
Take your time with it. 1 week isnt really much when it comes to practice. It sounds like from what you have said by the end of your comment that you also use a metronome and are using it very slow. This is great! No one can say how long this takes, it really does depend on how you learn, what you learn, when you learn and how all that just folds in together.
Hope this helps!
