WHAT?!?! You didn't inject your butt? It's ruined! Ruined, I tell ya! Just kidding. You'll find that pork butts are a very forgiving meat (within reason). I always inject mine, just my preference. I don't marinate, but if I get one that is not enhanced (hard to get around here) then I will brine it over night.
I never foil until I pull and then I add a little apple juice/apple cider for moisture. I usually will spray every once in a while with the same mixture while cooking (don't know if that really helps, but it gives the kids a chance to do something that they like to do). I try to cook mine between 225-250 and have even gotten good results when my temps got a little hotter 275 or so, but I don't recommend cooking at that heat on purpose.
Relax and enjoy!
IMBAS Certified MOINK Ball maker and IMBAS Sgt. At Arms.
And now, brethren, I commend you to God, and to the word of his grace, which is able to build you up, and to give you an inheritance among all them which are sanctified. [Acts 20:32 KJV]