Okay i just finished the Dragonborn storyline and I have gotta say it was AMAZING!! I actually almost easily killed Miraak the first time so i went and put the difficulty up to Master and it holy crap it was such an epic fight

After the fight as everyone here should know, we get the option to clear perks for the cost of dragon souls. My question: Can you read "Waking Dreams" and go back to Apocrypha to reset said perks at any time?? I need to know before I choose now, in case I can't come back and pick another.